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61 Cards in this Set
- Front
- Back
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A child throws a ball directly up in the air. At the top of its flight
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Its vertical velocity is zero
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2. The earth exerts a downward force on you of 700N as you walk down the street. According to Newton’s Third Law how much force do you exert on the Earth?
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700 N upward
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A car is traveling in a straight line at a constant speed. The total net force on the driver is
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zero
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If you push two skaters with identical amounts of force, which skater will accelerate more quickly?
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The skater with the greater mass
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You drop a ball from rest and after 1 second its velocity is 9.8 m/s. What is its velocity after 2 seconds of falling?
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19.6 m/s downward
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Where do you have the most gravitational potential energy?
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At the top of a mountain
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Hooke’s Law states that
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The restoring force of a spring is proportional to its distortion
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Which is an example of centripetal force?
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A boy riding a turning carousel
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When a bouncing ball is distorted from its equilibrium shape what kind of energy does it store?
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Elastic potential energy
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How does resonant energy make it possible for sound to shatter a crystal glass?
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The sound slowly transfers energy to the glass until it shatters
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What happens to the sound waves when you hear an echo in a cave?
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The cave walls are reflecting the sound waves
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The strings on a violin that produce the highest pitch are
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the thinnest, tightest strings
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the best example of a simple harmonic oscillator is
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a plucked guitar string
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The period of a pendulum depends on
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length and strength of gravity
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Polarization allows
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an electrically charged balloon to stick to a neutral wall
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Why shouldn’t you step out of a car that has been struck by lightening?
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You would complete the circuit and cause an electric current to flow
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A springboard diver leaps upward from the springboard, rises dramatically to a peak height, and than drops impressively into the water below the board. Neglect any influences of air or the atmosphere. During this trip, the diver experiences
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a constant downward net force.
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A steady, horizontal stream of water from a hose strikes a wall. As the water hits the wall, its velocity is forward, its acceleration is
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backward, and its pressure is increasing.
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If a child stands up on the seat of a playground swing, how will the swing’s period be affected?
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the period will decrease as the pendulum gets shorter.
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You are trying to loosen an ordinary screw that someone has jammed into your dormitory wall. Try as you may, you can't get that screw to turn at all. While you are twisting as hard as possible on the head of the screw, the net torque that the screw is experiencing is
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zero.
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You can bicycle up a particular hill in one of several gears, making the bicycle easier or harder to pedal. In going from rest at the bottom of the hill to rest at the top of the hill, which of the following quantities will be the same regardless of which gear you use?
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The force you exert on the pedals times the distance the pedals move in the direction of that force
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If you swing a full bucket of water over your head quickly enough, the water will stay in the bucket even when that bucket is upside-down. If you swing the bucket more slowly, you'll get wet. One way to understand these different behaviors is to note that
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inertia dominates the water's motion at high speeds, while gravity dominates at low speeds.
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Consider two automobile accidents in which identical cars are driven into a solid wall at 30 mph and 60 mph, respectively. Compared to the car traveling 30 mph, the car 60 mph transfers
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twice as much momentum into the wall and converts four times as much kinetic energy into other forms.
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When you jump on a trampoline, you stretch an elastic surface up and down. The two of you (you and the trampoline) have a combined total potential energy that changes as you bounce around. The point at which your combined total potential energy is lowest is when you are located
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at the equilibrium height to which you settle down if you stop jumping.
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You drop a ball from rest on a concrete floor and let it bounce twice. The first time it rises to 80% of its original height before descending again. The second time it rises to
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64% of its original height.
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Which of the following controls can cause an automobile to accelerate: the accelerator pedal, the brake pedal, and the steering wheel.
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all three.
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You shoot an arrow straight up, using a bow. Naturally, you run away before it comes back down. While the arrow is heading upward, but no longer touching the bow, the net force on it is
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downward and it is accelerating downward.
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You're seated in the last car of a roller coaster train and being pulled over the lip of the first plunging drop. As you go over this lip, you feel nearly weightless. This experience of weightlessness is more severe for you than it was for people in the first car of the train because you
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(A) are accelerating downward at a greater rate than the people in the first car.
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While some fires can be fought with hoses connected directly to fire hydrants, other fires require that the water first pass through the pumps inside a fire truck. Adding energy to the water with a pump allows that water to
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travel to greater heights, reach greater pressures, and achieve greater speeds.
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1. An object's ___ is the force exerted on it by gravity?
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weight
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2. As you watch people walk off the diving board at a pool, you notice that it bends downward by an amount proportional to each diver’s weight. This is because
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c) The diving board is acts like a spring and bends downward in proportion to the weight of each diver
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3. The time it takes a harmonic oscillator to complete one full cycle of its motion depends on
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a) How stiffly its restoring force pushes it back and forth and on its mass
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4. A water surface wave with a speed of 8.9 m/s has a wavelength of 17.8 m. What is its wave frequency?
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.5 Hz
Speed=wavelength x frequency |
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5. You mistakenly place a short steel wrench in the 3-T field near a strong magnet. The field magnetizes the wrench, and it develops a north pole of 1,095 A · m at its near end and an equal south pole at its distant end. Only the near end of the wrench is in the 3-T field and experiences a magnetic force. What force does the field exert in the wrench and its north pole?
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3,285N
[force = pole • magnetic field] |
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7. Halfway between the highest filled level and lowest unfilled level of an electron is
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a) The Fermi level—a hypothetical level that defines the top of this Fermi sea of electrons.
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Resistors are
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a) Ohmic devices
b) Devices that impede current c) Devices that produce a drop in voltage d) All of the above* |
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9. Collections of binary bits are represented by values of
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a) 0 & 1
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10. If the low-pressure neon vapor in a neon sign were replaced by a low-pressure mercury vapor, the sign would emit almost no visible light. Why not?
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c) Excited mercury atoms emit primarily invisible ultraviolet light.
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If you bring two magnetic compasses nearby, they will soon begin attracting one another. Why don't they repel?
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The two compass needles rotate until they have minimized their total magneostatic potential energies and thus the opposite poles will point toward one another.
-The compass needles will want to move toward equilibrium in which the total magneostatice potential energies are minimal which occurs with the opposite poles closest to one another and thus, the needles are attracted. |
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A particular lightbulb is designed to consume 40 W when operating on a car's 12-V DC electric power. If you supply that bulb with 12-V AC power from a transformer, how much power will it consume?
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40W
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A clothing rack hangs from the ceiling of a store and swings gently back and forth. You notice that the period of the rack's oscillation doesn't depend on how many dresses the rack is holding. Instead, its period depends only on
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its length and the strength of gravity
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You are walking with a full cup of coffee in your hand and it begins to slosh wildly in the cup. When you start walking slightly faster, the sloshing motion nearly vanishes. Why was the sloshing strongest when you were walking at the slower pace?
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Your steps were synchronized to the sloshing motion and you were transferring energy to the coffee's sloshing motion via resonant energy transfer.
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The metal wires from which most tank circuits are made have elelctrical resistances. Why do these resistances prevent charge from oscillating forever in a tank circuit and what happens to the tank circuit's energy as time passes?
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The wire's resistance wastes the tank circuit's energy as thermal energy which reduces the amount of charge sloshing in the tank circuit until the sloshing stops altogether.
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Why are most microwave TV dinners packaged in plastic rather than aluminum trays?
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Aluminum trays would reflect the microwaves which would result in improperly cooked food.
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The gate of a MOSFET is separated from the channel by a fantastically thin insulating layer. This layer is easily punctured by static electricity, yet the manufacturers continue to use thin layers. Why would thickening the insulating layer spoil the MOFSET's ability to respond to charge on its gate?
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The gate's charge must be very near the channel in order to attract opposite charges and draw the charge into the channel.
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If electrons were not Fermi particles, any number of them could occupy a particular level. How would these electrons tend to arrange themselves among the levels in an object?
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All electrons would be in the lowest energy level.
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If you hold a magnetic compass in a uniform magnetic field pointing northward, in which direction, if any, is the net magnetic force on the compass?
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There is no magnetic force direction
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If you pull down on the basket of a hanging grocery store scale so that it reads 15 N, how much downward force are you exerting on the basket?
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15 N
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When you put a positive magnet near a neutral wall:
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The wall will polarize and the negative electrons will move closer to the magnet, causing
a slight attraction |
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If you cut a magnet in half:
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It will result in 2 dipole magnets with the opposite pole of each magnet facing each other
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How many flux lines leave a magnet?
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The amount of flux lines that enter a magnet are equal to the amount of flux lines that
leave a magnet |
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Ferro magnets include:
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Iron
Refrigerator magnets Permanent magnets |
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If DC current is supplied to an AC motor:
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The AC motor will turn halfway and stop
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A Permanent magnet:
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Produces a high magnetic field with a small amount of mass
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Ohm's law states:
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The voltage drop is directly proportional to the current.
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A material is a conductor when:
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Some levels of the valance bands are empty and the electrons have somewhere to move
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An insulator can become a conductor if:
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Thermal energy is placed on the object providing enough energy for the electrons to
move to empty levels in the conduction band |
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An example of a resistor is:
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Light bulb filament that impedes current
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Small band gaps allow for:
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Less energy necessary to move electrons
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A diode:
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Allows for current to only flow in one direction
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A capacitator:
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Stores energy and separates charge
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