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165 Cards in this Set
- Front
- Back
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Chemistry is ______
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the study of matter and how matter changes
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Which of the following is NOT a correct inference that you can make about the burning of gasoline?
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The reaction is a physical change
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A chemical equation that shows the same number of each kind of atom on both sides of the equation is said to be
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balanced
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Anything that has mass and takes up space is considered
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matter
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What happens when chemical bonds break and new bonds form?
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a chemical reaction
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The only sure evidence for a chemical reaction is
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the production of one or more new substances
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A shorter, easier way to show chemical reactions, using symbols instead of words, is called a
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chemical equation
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The substances listed on the left side of a chemical equation are the
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reactants
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In chemical reactions, what does the principle of conservation of mass mean?
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matter is not created or destroyed
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Which two processes could be considered opposites?
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A synthesis reaction and a decomposition reaction
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A bottle of hydrogen peroxide that eventually turns into a bottle of water and oxygen gas is an example of a
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decomposition reaction
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A chemical reaction that absorbs energy in the form of heat is described as
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endothermic
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The minimum amount of energy that has to be added to start a reaction is the
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activation energy
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Which of the following does NOT increase the number of particles of a substance avaliable to react in a chemical reaction?
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adding a catalyst
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A material used to decrease the rate of a chemical reaction is a(n)
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inhibitor
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Which of the following is an example of how to supply activation energy to begin a reaction?
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heat the reaction flask on a hot plate
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A rapid reaction between oxygen and a fuel is known as
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combustion
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In what way can a fire be brought under control?
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remove oxygen
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What is the best form of fire safety?
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fire prevention
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The best way to put out a small kitchen fire is to
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cover it or use a home fire extinguisher
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The principle of conservation of mass is true
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for reactions in both open and closed systems
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When a chemical reaction takes place in an open system,
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matter can enter from or escape to the surroundings
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In a chemical equation, number often appear in fromt of a chemical formula. These numbers tell you the
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number of molecules or atoms of each substance in the reaction
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Every chemical reaction involves a change in
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energy
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Chemicals that act as biological catalysts by speeding up reactions in living things are
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enzymes
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The number placed below an element's symbol in a chemical formula is called a
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subscript
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AS in the case of unlike magnetic poles, unlike electric charges
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attract each other
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The buildup of charges on an object is called
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static electricity
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Clothes in a dryer acquire static cling by
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friction
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The loss of static electricity as electric charges move off an object is called
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static discharge
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Suppose you acquire a positive charge from walking across a carpet. You then touch a doorknob and receive a shock. This leaves you
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electrically neutral
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The typ of energy that depends on position is called
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potential energy
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What causes charges to move in a circuit?
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voltage
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If an electric water heater uses 40 kW of power and runs for 8 hours, what is the total amount of energy used?
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320 kilowatt-hours
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An electric current will always follow
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the path of least resistance
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According to Ohm's law, what is the resistance of a light if the voltage is 9.0 volts and the current is 0.30 amps?
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30 ohms
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In a series circuit with three bulbs,
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all of the bilbs become dimmer as more bulbs are added
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In a series circuit with three bulbs, adding another bulb will
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make all the bulbs dimmer
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In a parallel circuit with three bulbs,
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current from each bulb has its own path
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A device to measure electrical potential energy difference, or voltage, is called a(n)
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voltmeter
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A connection that allows current to take the pth of least resistance is called a
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short circuit
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What is a disadvantage of using fuses?
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When a fuse burns out, it cannot be used again
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What effect would a current of grerater than 0.2 amo have on your body?
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It could cause burns and stop your heart
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The charge on a proton is
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positive, and the charge on an electron is negative
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An instrument that can detect the presence of an electric charge is a(n)
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electroscope
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A device that creates a potential difference in an electric circuit is a(n)
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voltage source
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A complete, unbroken path through which electric charges can easily flow is a(n)
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electric circuit
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Materials that allow the charges of an electric current to move freely through them are called
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conductors
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An example of an insulator is
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rubber
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A device used to open and close an electric circuit is a(n)
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switch
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Power is calculated by multiplying voltage by
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current
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The ampere is a unit of
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electric current
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What parts of the cell are used to connect an electrochemical cell to a circuit?
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terminals
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If a household's voltage is 120 volts, what is the power rating of a light bulb with 0.5 amps of current flowing through it?
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60 watts
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A device that transforms stored chemical energy into electrical energy is a(n)
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electrochemical cell
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When an object's distance from another object is changing
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it is in motion
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the basic SI unitl of length
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meter
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Speed equals distance divided by
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time
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When you know both the speed and direction of an objects motion, you know the
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velocity of the object
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You can show the motion of an object on a line graph in which you plot distance against
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time
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The steepness of a line on a graph is called
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slope
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The rate at which velocity changes is called
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acceleration
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Which of these is an example of deceleration?
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a car approaching a red light
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To determine the acceleration rate of an object, you must calculate the change in sped during each unit of
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time
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If sped is measured in kilometers per hour and time is measured in house, the unit of acceleration is
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kilometers per hour per hour
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Average speed is
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the total distance traveled divided by the total time
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A place or object used for comparison to determine if something is in motion is called
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A reference point
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On a grap showing distance versus time, a horizontal line represents an object that is
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not moving at all
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If you know the distance an object has traveled in a certain amount of time, you can determine
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the speed of the object
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It is rare for any motion to
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stay the same for very long
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If the speed of an object does NOT change, the object is traveling at a
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constant speed
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Changing a direction is an example of a kind of
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acceleration
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If a bicyclist travels 30 kilometers in 2 hours, her average speed is
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15 km/h
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The moon accelerates because it is
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continuously changing direction
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If you know a car traveled 300 kilometers in 3 hours, you can find its
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average speed
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In an acceleration graph showing sped versus time, a straight line shows the acceleration is
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constant
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A classroom measures 4.33 meters wide. How wide is the classroom in centimeters?
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433cm
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Kilo- is a prefix that means
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one hundered
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A car travels 85 km in the firs thour of a trip. The car continues to travel for 2 more hours and travels 200 km. What is the average speed of the car for the trip?
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95 km/h
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A runner rounding a curve on a track at a constant speed is an example of what type of acceleration?
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changing direction
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What is an example of exerting force?
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a carpenter hammering a nail
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What happens when 2 forces act in the same direction?
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They add together
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The tendency of an object to resist change in its motion is known as
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inertia
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The greater the mass of an object,
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the greater its inertia
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The force of gravity on a person or object on the surface of a planet is called
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weight
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One way to increase acceleration is by
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decreasing mass
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The force that one surface exerts on another when the two rub against each other is called
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friction
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What is an example of rolling friction?
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bike tires on the road as you ride
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When the only force acting on a falling object is gravity, the object is said to be
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in free fall
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Air resistance is a type of
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friction
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The force of gravity ona person or object at the surface of a planet is known as
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weight
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The law of universal gravitation states that any two objects in the universe, without exception,
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create friction
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Forces can be added together only if they are
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acting on the same object
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The product of an object's mass and velocity is called its
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momentum
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According to the law of conservation of momentum, when 2 objects collide in the absence of friction,
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velocity decreases
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The achievement of lifting a rocket off the ground and into space can be explained by
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the law of conservation of momentum
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What is required for a rocket to lift off into space?
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thrust that is greater than Earth's gravity
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An object that travels around another object in spance is called a(n)
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satellite
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Any force that causes an object to move in a circle is called a(n)
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centripetal force
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In physical science, a push or a pull is called a(n)
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force
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The amount of matter in an object is called its
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mass
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The force tha pulls falling objects toward Earth is called
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gravity
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Objects falling through air experience a type of friction called
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air resistance
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The SI unit for forve is the
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newton
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Balanced forces acting on an obbject
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never change the object's motion
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The total momentum of a group of objects is conserved unless
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outside forces act on the objects
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Snowshoes enable a person to walk on deeo snow because the snowshoes
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increase the area over which the person's weight is distributed
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A unit of pressure is called a
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pascal
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Air pressure exerted equally on an object from different directions is
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balanced pressure
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Given that the air pressure outside your body is so great, why aren't you crushed?
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Pressure inside your body balances the air pressure outside your body
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Air pressure decreases as
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elevation increases
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Water pressure increases as
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depth increases
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Why type of substace does Pascal's principle deal with?
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fluids
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One application of Pascal's principle is
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a hydraulic car lift
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What scientific rule describes why water squirts from a plastic bottle when it is squeezed?
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Pascal's principle
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What does a hydraulic system do?
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multiply force
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Which of the following is true of the buoyant force?
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it acts in the upward direction
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What effect does a buoyant force have on a submerged object?
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It causes a net forve acting upward on the object
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If an object floats, the volume of displaced water is equal to the volume of
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the portion of the object that is submerged
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What scientific rule states that the buoyant force on an object is equal to the weight of the fluid displaced by the object?
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Archimedes' principle
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WHen water fills a submarine's flotation tanks, the overall density of the submarine
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increases
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A ship stays afloat as long as the buoyant force is
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equal to the ship's weight
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Smoke rises upa chimney partly because of
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Bernoulli's principle
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Bernoulli's principle helps to explain
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flight
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The mass per unit volume of a substance is its
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density
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AN object that is more dense than the fluid in which it is immersed will
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sink
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Which of the folloring of the substances is the LEAST dense?
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wood
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Pressure can be measured in units of
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newtons per square meter
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A substance whose shpae can easily change is a
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fluid
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A material that can easily flow is called a
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fluid
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What scientific rule states that the pressure exerted by a moving stream of fluid is less thsn the pressure of the surrounding fluid?
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Bernoulli's principle
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The pressure in the deepest parts of the ocean is roughly how many times the usual air pressure you experience?
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1,000
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WHich of these multiplies a force by transmitting it to a large surface area?
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a hydraulic system
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The braking system on a car is an example of
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a hydraulic system
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A barometer is used to measure pressure
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in the atmosphere
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Which waves have some electrical properties and some magnetic properties?
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electromagnetic waves
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Electromagnetic waves can transfer energy without a(n)
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medium
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Light that has passed through a polarizing filter is called
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polarized light
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In a vacuum, all electromagnetic waves have the same
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speed
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Visible light has a higher frequency than
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infrared rays
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The range of electromagnetic waves placed in a certain order is called the
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electromagnetic spectrum
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The electromagnetic waves with the highest frequencies are called
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gamma rays
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When a police officer uses radar for sped control, the officer is using what kind of electromagnetic waves?
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radio waves
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Visib;e light can be separated into various colors to form a(n)
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spectrum
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Which type of light glows when a fliament inside it gets hot?
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incandescent
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Which light bulbs are coated on the inside with a powder?
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fluorescent
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If something vibrates one million times per second, it has a frequency of
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1 megahertz
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FM signals travel as changes in
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the frequency of the wave
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What kind of waves do cellular telephones use to transmit and receive signals?
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microwaves
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Broadcasting stations can send their signals around the world using
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television satellites
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Flobal Positioning System signals can tell you
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your exact location on Earth
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What is transferred by electromagnetic waves?
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electromagnetic radiation
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About how much faster than sound aree electromagnetic waves?
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One million times faster
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Which type of light bulb is commonly used in advertising signs and decoration?
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neon
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Which electromagnetic waves have the longest wavelength's and lowest frequencies?
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radio waves
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On AM broadcasts, what remains constant/
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the frequency
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For each cell, or geographical area, a cellular phone system requires
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a tower
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The images made by an infrared camera are called
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thermograms
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Which of the following is true of ultraviolent rays?
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They can help your body produce vitamin D
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The Global Positioning System (GPS) was originally designed for use by
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the military
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An instrument used to view different colors of light produced by each type of light bulb is called a(n)
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spectroscope
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A packet of light energy is called a
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photon
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The speed of an electromagnetic wave is equal to
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wavelength times frequency
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What do cell phones require to work?
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a cellular system
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Cell phone signals are transmitted by
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radio waves
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