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138 Cards in this Set
- Front
- Back
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Which one of the following situations is not possible? |
A body travels with a constant velocity and a time-varying acceleration |
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A child playing with very smooth blocks on a very smooth, (frictionless), when the child’s hand is no longer touching the block, the block continues to move with constant velocity because:
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there is no net force acting on the block |
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A rock is thrown from the roof of a tall building. While it is falling towards the ground, the force of gravity acting on it is:
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equal to its weight |
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A bowling ball rolls down an alley and hits a bowling pin. Which statement below is true about the magnitudes of the forces exerted during the impact?
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the magnitude of the forces that they exert on each are equal |
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Two objects with different masses collide and stick to each other. Compared to before the collision, the system of two objects after the collision has:
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the same total momentum but less total kinetic energy |
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Near the surface of the earth, the fluid at the bottom of a container is:
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under more pressure than the fluid on the top |
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Suppose you work in the E.R. and a choking patient comes in with their trachea half obstructed. (The diameter is half of what it was before the obstruction.) You manage to correct the problem and send them on their way safely, explaining that such obstructions are particularly dangerous because:
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a half-blocked airway passes only 1/16 the regular amount of air |
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The water is now boiling. To boil the eggs using the least amount of gas do the following:
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turn the flame on low, so that the water is barely boiling |
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When I bake a sweet potato in the oven, I always put it on a thin sheet of aluminum foil. This is because sometimes the potato exudes a sugary juice that burns and makes a hard-to-clean-up mess if it drips on the bottom of the oven. When I’m ready to take the potato out of the hot (400o F) oven after an hour of cooking, I find I can pick up the aluminum foil with my bare hands without getting burned. Why?
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Because the aluminum foil has a low specific heat and not much mass, so even at a high temperature it doesn’t have a lot of thermal energy in it to burn me.
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A microwave oven is rated at 1000 W. At sea level, how long will it take to bring a cup of water (250 ml) to boil from room temperature (20 °C)? Assume the specific heat capacity of the cup itself is negligible.(for water: cw = 4190 J/(kg K), 1 ml = 1 cm3 = 1 g)
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84 s |
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A 1.9 kg block of copper is heated at atmospheric pressure such that its temperature increases from 3 oC to 61 oC. How much heat (in J) is absorbed by the block of copper?The specific heat of copper is 0.092 (kcal/(kgoC))1 kcal = 4186 J
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42,439
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At which temperature do the molecules of an ideal gas have 3 times the kinetic energy they have at 32oF?
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546 oC
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A tank having a volume of 0.14 m3 contains helium gas at 150 atm.How many balloons can the tank blow up, if each filled balloon is a sphere of radius 0.16 m at an absolute pressure of 1.2 atm?Enter an integer.
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1,020
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How much thermal energy (in kcal) is required to change a 31 g ice cube from a solid at - 18.8 oC to steam at 8.6 oC above boiling?
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22.7 |
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Two thermometers, one calibrated in oF and one in oC, are used to measure the same temperature. The numerical reading on the Fahrenheit thermometer...
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may be equal, higher or lower than that on the Celsius thermometer, depending on the temperature.
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If you double the radiating surface area of a star while keeping its temperature constant, its power output increases by a factor of
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2
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A refrigerator has a coefficient of performance equal to 5.1. If the refrigerator absorbs 216.6 J of thermal energy from a cold reservoir in each cycle, find the work done on the system each cycle (in J).Enter a number with one digit behind the decimal point.
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42.5
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You fill two identical mugs with coffee, but the coffee in one mug is at a higher temperature than that in the other mug. You place the two mugs simultaneously in a microwave oven and turn it on briefly. As a result, you add 1 Joule of thermal energy to each mug. Which mug experiences the larger increase in entropy (if any)?
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The mug containing the colder coffee experiences the larger increase in entropy.
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Living cells constitute a low entropy state of matter. Living cells
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can exist because they help increase the entropy of the rest of the universe.
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The volume of a gaseous sample is increased from V1 to V2 in three different ways.A-->B: isobaric processA-->C: isothermal processA-->D: adiabatic processThen the work done by the gas is
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maximum in the isobaric process.
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In the cyclic process on an ideal gas shown in the adjoining PV diagram, what is the net work done by the gas during the cycle?
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4 PV
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The P-V diagram below shows six curved paths (connected by vertical paths) that can be followed by a gas. Which two of them should be part of a closed cycle if the net work done by the gas is to be at its maximum positive value?
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c and e
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What is the maximum coefficient of performance of a heat pump that takes heat from outdoors at a temperature of -14.1 oC and delivers it indoors at a temperatute of 18.1 oC.Enter an number with one digit behind the decimal point.
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9
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In any process, the maximum amount of mechanical energy that can be converted into thermal energy
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is 100% |
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A standing wave is established on a 1.2 m long string fixed at both ends. The string vibrates in four segments when driven at 120 Hz. What is the fundamental frequency?
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30 Hz
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A sinusoidal force with a given amplitude is applied to an oscillator. To maintain the largest amplitude oscillation, the frequency of the applied force should be
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the same as the natural frequency of the oscillator.
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A traveling wave is described by the equation y(x,t) =( 0.14 m) cos(25 x + 181 t ), where x is measured in meter and t in seconds. What is the velocity of this wave in units of m/s?
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-7.2 |
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We observe the harmonic motion of an object. Its position as a function of time shown in the graph below is given by x = 1* cos(π t), where x is measured in meter and t is measured in seconds. What are the amplitude (A), the period (T), and frequency (f) of the motion?
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A: 1 m, T: 2 s, f: 0.5 Hz
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A 0.500 kg mass is attached to a spring of constant 150 N/m. A driving force F(t) = (12.0 N)cos(ωt) is applied to the mass, and the damping coefficient b is 6.00 Ns/m. What is the amplitude of the steady-state motion if ω is equal to half of the natural frequency ω0 of the system?
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9.7 cm |
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The mechanical energy of a mass-spring system is 0.368 J. If the force constant of the spring of 278 N/m and the mass is 0.67 kg, what is the amplitude of the oscillatory motion in cm?
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5.1 |
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A vibrating source generates a harmonic wave on a string under constant tension. If the power delivered to the string is doubled, by what factor does the amplitude change?
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1.41 |
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A rope has a mass of 0.8 kg and a length of 11.7 m. It is fixed at both ends. If the frequency of the first harmonic on this rope is 0.85 Hz, what is the tension of this rope in N?
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27.05 |
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Pure sound notes from two sources make the molecules of air at a location vibrate simple harmonically in accordance with the equations y1 = 0.008 sin (604 π t) and y2= 0.007 sin (610 π t), respectively. The number of beats heard by a person at the location will be
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3 |
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What is the approximate period of the sound waves shown here? (The speed of sound in air is ~340 m/s.)
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.0037 s |
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Your friends decide to play a prank on you and lock you in a room with two speakers making an incessant hum at 680 Hz. Which of the following locations would deafen the hum the most? (Take the speed of sound to be 340 m/s.)
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3.00 m away from speaker A; 3.75 m away from speaker B
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The third harmonic in a tube with one open end has a frequency of 1,343 Hz. What is the length of the tube in meter, if the speed of sound is 349.8 m/s?
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.2 |
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For a sound wave of frequency 440 Hz, what is the wavelength (i) in air (propagation speed, v = 3.3 * 102 m/s)?(ii) in water (propagation speed, v = 1.5 * 103 m/s)?
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(i) 0.75 m, (ii) 3.41 m
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Suppose you have a tube 0.25 m long with a speaker at one end and with the other end open. If you gradually increase the frequency of the speaker from zero at about what approximate frequency will you hear the first resonance?
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350 Hz
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A source emits a sound of 149 Hz. It is moving towards the right with a speed of 35 m/s and approaching an observer who is moving towards the left with a speed of 36 m/s. what is the frequency heard by the observer?
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184 |
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The speed of sound waves having a frequency of 256 Hz compared to the speed of a sound wave having a frequency of 512 Hz is
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the same |
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Heat is added at a rate of 10.0 kJ/min to a 0.5 kg solid sample starting at t = 0 min. What is the melting temperature of the sample?
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283 K
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What is vrms (root mean square speed) of a He atom in m/s at 289 K temperature?
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1343 |
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The temperature in oF is -75. What is the temperature in K?
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213.71 |
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At a given temperature
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all the molecules in a gas have the same average kinetic energy.
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Calculate the magnitude of rate of heat flow (in kJ/s = kiloWatts) by conduction through 2 cm thick Aluminum plate with an area of 4 m2, if the temperature difference between the two sides is 15.1 oC.Thermal conductivity of Al: 4.9*10-2 (kcal/sec)/(oC m)
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619 |
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A copper pipe is 20 m long at 0 oC. If the temperature is increased to 47 oC, by how much (in mm) does its length change?Linear expansion coefficients α for copper: 17*10-6/oCEnter a number with two digits behind the decimal point.
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15.98 |
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A container with a piston-lid contains an ideal gas at temperature Ti = 27 oC (300 K) and a volume V0. The temperature is increased to Tf = 127 oC while the pressure is kept constant. What is the new volume?
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(4/3) V0
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A star with a surface temperature of 6000 K appears yellow in color. A star with a surface temperature of 4000 K will
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appear reddish in color
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In any process, the maximum amount of heat that can be converted into mechanical energy
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depends on the intake and exhaust temperatures.
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A thermodynamic system undergoes a process in which its internal energy decreases by 686 J.If at the same time 619 J of thermal energy is transferred to it, how much work (in J) is done by the system?
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1305 |
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A 1 kg block of aluminum is heated at atmospheric pressure such that its temperature increases from 11 oC to 78 oC. What is the change in the internal energy (in J) of the block of aluminum?
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60,300 |
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A heat engine extracts usable work by permitting
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heat to flow from a hotter object to a colder object.
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Gas in a container is at a pressure of 1.7 atm and a volume of 6.3 m3. What is the work (In kJ) done by the gas if it expands at constant pressure to a volume 10.9 m3?
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792 |
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A gas is in a container with a piston lid and is taken from thermodynamic state, 1, to a new thermo-dynamic state, 2, by several different paths, A, B, and C, in the P-V plane. The internal energy of the gas increases during the process. The work done by the gas is largest for path
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A |
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Assume we can change the equilibrium state of a system via two different processes. Assume that the initial and the final state are the same. Which of the quantities ΔU, ΔQ, ΔW, and ΔT must be the same for the two processes?
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only ΔU and ΔT
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While a guitar string is vibrating, you gently touch the midpoint of the string to ensure that the string does not vibrate at that point. The lowest-frequency standing wave that could be present on the string
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vibrates at twice the fundamental frequency
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A mass-spring system oscillates with an amplitude of 7 cm. If the force constant of the spring of 151 N/m and the mass is 0.66 kg, what is the magnitude of the maximum acceleration of the mass in m/s2?
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16 |
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An object on the end of a spring is oscillating in simple harmonic motion. If the amplitude A of oscillation is doubled, how does this affect the oscillation period T and the object’s maximum speed vmax?
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T remains the same and vmax doubles
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What is the period (in s) of a simple pendulum of length 0.69 m and mass 0.18 kg near the surface of a planet where the gravitational acceleration is 11.6 m/s2?
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1.53 |
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A hand moves to produce a periodic wave. You are making a movie. You freeze the movie and get this snapshot. If you advance the movie one frame, the knot at point A would be
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lower |
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You are watching a semi truck bounce up and down on a spring. (Yep it’s a toy.) At the topmost point in the truck’s path,
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the truck’s velocity is zero but its acceleration is downward
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How many nodes and antinodes are shown in the standing wave below?
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three nodes and two antinodes
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A grandfather clock is running slow. The period of its pendulum is too long. To shorten the period and make the clock run faster, you should.
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decrease the length of the pendulum
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A box with a total surface area of 1.2 m2 and a wall thickness of 4 cm is made of an insulating material. A 10 W electric heater inside the box maintains the inside temperature at 15 oC above the outside temperature. What is the thermal conductivity of the insulating material in units of kcal/(s oC m)?
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5.3X10^-6
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The temperature on a nice summer day is 84 oF. What is the temperature on the absolute (Kelvin) temperature scale?
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302 K
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The temperature in a furnace used to melt Aluminum is 660 oC. What is the average kinetic energy of the air molecules in the furnace?
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1.93X10^-20
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On a humid summer day, perspiration does not cool you off much. Why? |
The air is almost saturated with water vapor and there is almost no net evaporation
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In a mixture of hydrogen, oxygen, and nitrogen gases at a given temperature, the molecules having the greatest average speed are those of
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Hydrogen |
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A 1 kg block of aluminum is heated at atmospheric pressure such that its temperature increases from 22 oC to 40 oC. What is the change in the internal energy (in J) of the block of aluminum?
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16200 J
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A hypothetical engine operates in a cycle taking in 10,000 J from a hot reservoir and 5000 J from a cold reservoir. In the cycle it performs 15,000 J of work. Such an engine
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Obeys the first law but violates the second law.
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An ideal reversible engine takes in 5 kJ of energy via heat transferred in from a 500 K burner and exhausts heat at 300 K during each closed cycle in the PV plane. The amount of heat exhausted at 300 K each cycle is
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3 KJ |
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Pressure vs. volume graphs for a certain gas undergoing five different cyclic processes are shown to the right. During which cycle does the gas do the greatest positive work?
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IV |
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Which of the statements below is wrong?
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The net force acting on the pendulum bob is F = -mgsinθ. The period increases with amplitude because this force increases faster than harmonic restoring force F= -mgθ.
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A 200 Hz sound wave has a measured wavelength of 1.675 m. Which of the following statements are true? You can choose more than one statement.
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-V=Fλ= 1.675(200) = 335 so The speed of the 200 Hz wave is ~335 m/s
-1.675/2 = 83.75 so The wavelength of the 400 Hz wave is ~ 80 - 85 cm |
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A 0.5 kg mass oscillates about the equilibrium position on a vertical spring with spring constant 10 N/m. Where is its equilibrium position measured from the unstretched spring position (without the hanging mass)?
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.49 m |
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A string is clamped at both ends and then plucked so that it vibrates in a standing mode between two extreme positions a and c. Let upward motion correspond to positive velocities. When the string is in position b, the instantaneous velocity of points along the string
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Is zero, positive, or negative depending on the position along the string.
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A point source of sound waves emits a disturbance with a power of 50 W = 50 J/s into a surrounding homogeneous medium. What is the intensity of the sound at a distance of 10 m from the source?
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.04 W/m^2
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A sine wave and a square wave cannot have the same
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Tone Quality
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In the figure below, two point sources S1 and S2, which are in phase, emit identical sound waves of wavelength 2.0 m. If L1 = 39 m and L2 = 36 m, what type of interference occurs at point P?
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Destructive interference
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The intensity of sound wave A is 100 times that of sound wave B. Relative to wave B the sound level of wave A is
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+20 db
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A ball is thrown directly downward with an initial speed of 8 m/s from a height of 30 m. After what time interval does the ball strike the ground?
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1.78 seconds
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An object with mass m moves through free space with constant velocity. The magnitude of the force required to maintain this motion is equal to
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zero |
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Can two force vectors of unequal magnitude sum to zero net force?
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No |
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Can three force vectors of equal magnitude sum to zero net force?
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Yes |
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A car's speed changes from 20 mph to 60 mph. By what factor does its kinetic energy change?
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9 |
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Suppose you are spending your weekend on roller skates trying to get momentum from somewhere. Which of the following will give you momentum in the north direction?
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Throw your keys southward
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Suppose you have an aquarium. You have a solid plastic decoration and a rock of about the same volume but the rock has twice the mass. Both are totally submerged in the water. The buoyant force on the plastic object is about
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the same as that on the rock.
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Consider two specimens of ideal gas at the same temperature. The molecules in specimen #1 have greater molar mass than molecules in specimen #2. How do the root-mean-square or RMS speeds, Vrms = <v^2>, per molecule, <KE> = 1/2m<v^2>, compare in the two specimens? |
Vrms is greater in specimen #2; <KE> is the same in both specimens |
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A steel bridge is built in several segments, each 20 m long. The gap between segments is 2 cm at 18 degrees C. What is the maximum temperature that the bridge can manage before buckling? |
95 degrees C |
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A chair has a wooden seat but metal legs. The chair legs feel colder to the touch than does the seat. Why? |
The metal has a higher thermal conductivity than the wood |
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Assume that a naked human body has a surface are of 1.5 m^2 and a surface temperature of 32 degrees C. If the surroundings are at a temperature of 16 degrees C, calculate the net rate of heat loss by the body due to radiation. Assume an emissivity of 1. |
143 W |
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It is possible for heat to flow across vacuum? |
True |
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People fighting forest fires care emergency tents that have shiny aluminum outer surface. If there is trouble, a fire fighter can lie under the tent to block the heat from burning trees overhead. The tent helps because |
radiation carries heat downward toward the fire fighter and the aluminum tent reflects most of that radiation |
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A pitcher contains .50 kg of liquid water of ice at 0 degrees C. You let heat flow into the pitcher until there is .75 kg of liquid water and .25 kg of ice. During this process, |
the temperature of the ice-water mixture remains the same. |
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Ice initially at -20 degrees C is to be turned into steam at 130 degrees C. To figure out how much heat is required, how many separate terms will there be? |
5 |
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Orange growers in Florida spray their trees with water when they expect a freeze. Why does this work? |
If a mixed phase of water and ice is present, the temperature does not drop below 0 degrees C |
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Your dryer is broken, so you have to hang your wet clothes from the washing machine outside to dry. Under which conditions would your clothes dry the fastest? |
When it is 74 degrees F with 50% relative humidity |
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Is it possible for heat to enter a system while the temperature of the system to does not change? |
Yes |
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5 moles of a monatomic gas has its pressure increased from 10^5 Pa to 2*10^5 Pa. This process occurs at a constant volume of .1 m^3. Determine the change in the internal energy of the gas. |
15000 J |
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Consider the change a gas undergoes as it transitions from point c to point a in the PV diagram. What type of process is this? |
Isobaric |
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An ideal gas in a closed container with a piston lid is taken from thermodynamic state, 1, to a new thermodynamic state, 2, by an isothermal path as shown in the P-V plane. The internal energy change during this process is |
zero, because it is an isothermal process |
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An ideal gas in a closed container with a piston lid is taken from thermodynamic state, 1, to a new thermodynamic state, 2, by an isothermal path as shown below in the P-V plane. The heat transfer into the gas during this process is |
positive |
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Is it possible to cool down a well insulated room on a hot summer day by leaving the refrigerator door open, and using the refrigerator as an air conditioner? |
No |
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The _____ the temperature difference between hot and cold, the larger the fraction of heat you can divert and transform into ________ |
larger; work |
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We flip a coin 10 times. Define a macrostate to be the number of heads. Define each micro state as a particular sequence of heads and tails. Some micro states for coin flips are listed below. "H" stands for heads and "T" stands for tails. Rank the micro states from most likely to least likely to occur |
V1) = III) = II) = I) |
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Two dice are thrown. Let the macrostate be the sum of the tow numbers on the top faces. What is the multiplicity of the macrostate "4"? |
3 |
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Why does heat, of itself, not flow from a cold to a hot object, if it is allowed by Newton's laws? |
This would require a large departure from equilibrium, which is extremely unlikely |
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A gas, confined to an insulated cylinder, is compressed adiabatically (and reversibly) to half its original volume. Does the entropy of the gas increase, decrease, or remain unchanged during this process? |
It remains unchanged |
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A sample of water at 0 degrees C is slowly converted into ice at 0 degrees C? The entropy of the same changes by deltaS = -.586 kcal/K. What is the mass of the sample? |
2 kg |
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Position, velocity and acceleration of an oscillating mass on a spring are shown as a function of time. What is the period of the oscillations? |
2.5 s |
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Position, velocity and acceleration of an oscillating mass on a spring are shown as a function of time. If the mass is 1 kg, what is the spring constant in N/m?
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~6 |
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Measure the frequency or period of a .1 kg mass oscillating on a spring. What is the spring constant of this spring? |
~3 N/m |
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A simple pendulum consists of a point mass m suspended by a massless, unstretchable string of length L. If the mass is doubled while the length of the string remains the same, the period of the pendulum... |
remains unchanged |
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A simple pendulum of length L oscillates back and forth 10 times per second. By what factor do you have to change its length to make it oscillate back and forth only 5 times per second? |
Increase the length by a factor of 4 |
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You are watching a mass oscillate on a spring. The initial amplitude is 40 cm. The amplitude halves after 10 s. How long does it take for the amplitude of the oscillation to decrease to 5 cm? |
30 s |
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A wave traveling in the +x direction is described by the equation y= .1 sin (10x-100t), where x and y are in meters and t is in seconds. Calculate (i) the wavelength, (ii) the period, (iii) the speed, and (iv) the amplitude of the wave |
(i) .63m, (ii) .063 s, (iii) 10 m/s, (iv) .1m |
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If you double the wavelength of a wave on a string under fixed tension, what happens to the wave speed v and the wave frequency f? |
v is unchanged and f is halved |
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The four strings of a musical instrument are all made of the same material and are under the same tension, but have different thickness. Waves travel.... |
fastest on the thinnest strinrg |
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Which of the following wave functions describe a wave that moves in the -x-direction? 1.) y(x,t) = A sin (-kx - wt) 2.) y (x,t) = A sin (kx+ wt) 3.) y (x,t) = A cos (kx + wt) |
1, 2, and 3 |
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A string of length 100 cm is held fixed at both ends and vibrates in a standing wave pattern. The first harmonic is shown. The wavelengths of the standing waves making up the pattern cannot be |
400 cm |
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Which sound travel the fastest through air? |
All sound travels at the same speed through air |
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A pure sound notes from a sources make the molecules of air at a location vibrate simple harmonically in accordance with the equation y1 = .008 sin (302 pi t). What is the frequency of the sound waves? |
151 HZ |
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If the intensity of a 40 dB sound is increased to 80 dB, the intensity in W/m^2 increases by a factor of |
10^4 |
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Two flutists are tuning up. If the conductor hears the beat frequency increasing, are the two flute frequencies getting closer together or farther apart? |
farther apart |
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If delta = 1 m and the speed of sound is 340 m/s, which statement is correct? |
All of the above statements are correct |
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Organ pipe B is open at both ends and is half as long as organ pipe A, which is open at one end, as shown. (i) the ratio of their fundamental wavelengths (ii) the ratio of their fundamental frequencies |
(i) 4:1 (ii) 1:4 |
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As a sound source approaches and then moves past a stationary observer, the observer will hear |
a sudden drop in pitch |
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When a car is at rest, its horn emits a sound wave of wavelength .55 m. A person standing in the middle of the street hears the horn with a frequency of 560 Hz. If the speed of sound is 330 m/s, should the person jump out of the way? |
No |
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The velocity versus time graph to the right represents the motion of an object moving in one dimension along the x-axis. The velocity of the object is always positive |
True |
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The diagram shows the trajectory of a golf ball. Which set of arrows shows the direction of the acceleration at points P and Q respectively? |
B |
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The positions of a dot is shown at successive 1-second time intervals. Which statements are true? (A) The dot is moving with constant speed (B) The dot is moving with constant velocity (C) The dot is accelerating |
A and C |
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Assume the car is accelerating towards the right and its speed is increasing. A cup of coffee left on the roof is accelerating with the car at the same rate. What is the direction of the frictional force on the cup? |
Towards the right |
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Your friend asks you to stand perfectly still holding up a weight bar with weights while he takes a picture. Are you doing work during this time? |
No |
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You need to loosen a very tight bolt. You have one wrench and you exert maximum force. Which configuration shown below gives you maximum chance of success? |
C |
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A disk spinning with angular velocity w as shown. It begins to speed up. While it is speeding up, what are the (i) directions of its angular velocity w (ii) and its angular acceleration a? |
C, C |
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Water with air bubbles flows through a pipe that becomes narrower. Compared to the wider region, bubbles in the narrow region are |
bigger |
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A string of length 100 cm is held fixed at both ends and vibrates in a standing wave pattern. The first harmonic is shown. The wavelengths of the standing waves making up the pattern cannot be |
400 cm |
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You are trying to bring a pot of water to a boil, to boil some eggs. To use the least amount of gas (energy), do the following |
turn the flame on high |
