Final: Work and Energy Flashcards

1
Q

which of the following processes require the most work?

A

a person lifts a 1 kg weight 1 m off the floor

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2
Q

a man pushes a crate along a factory floor by exerting a force of 55N. If the crate moves a distance of 4 m, how much work does the man perform?

A

220 N

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3
Q

what are the units of power

A

watts, horsepower, joules per second (all of the above)

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4
Q

which is not a simple machine?

A

a pair of scissors

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5
Q

which is an example of a wheel and an axle

A

a screwdriver

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6
Q

which is not in the inclined plane family

A

a wheel and axle

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7
Q

which statement about work and energy is not true

A

work and energy are always equal

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8
Q

a medicine ball has a mass of 5 kg and is thrown with a speed of 2 m/s. what is its kinetic energy?

A

500 J

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9
Q

the kind of energy associated with atomic bonds is

A

chemical energy

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10
Q

a pendulum is swinging back and forth and has a kinetic energy of 400 J at a particular point in its path. Which statement is not true?

A

both the kinetic and potential energy are decreasing

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11
Q

the brakes on a car exert a force of 6000 N in getting the car to stop. If the work done by the brakes is 120000 N in coming to a stop, how many meters did the car travel after the driver applied the brakes?

A

20 m

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12
Q

an object has a kinetic energy of 810 J after falling a certain distance. if the mass of the object is 20 kg, what is the speed of the object at this time?

A

9 m/s

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13
Q

a quantity that measures the effects of a force acting over a distance is called

A

work

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14
Q

a quantity that measures how much a machine multiplies force or distance is called

A

mechanical advantage

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15
Q

all levers have a rigid arm that turns around a point called the

A

fulcrum

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16
Q

a ____ is an inclined plane wrapped around a cylinder

A

screw

17
Q

the ability to do work is a definition of

A

energy