Chapter 12 ReviewWork and Energy

The transfer of energy to a body by the application of a force that causes the body to move in the direction of the force is called

A. powerB. workC. distanceD. mechanical advantage

A boy exerts an average force of 65 N when he lifts a box 1.2 meters. How much work did he do?

A. 0 JB. 54 JC. 66 JD. 78 J

________ is defined as the rate at which work is done.

A. PowerB. JouleC. SpeedD. Mechanical advantage

Calculate the mechanical advantage of a wrench that allows you to move a bolt 0.01 m by moving the handle 0.50 m.

A. 0.05B. 0.50C. 5.0D. 50

How much power is required to lift a 30 N chair 0.20 m in 2 sec?

A. 1 WattB. 3 WattsC. 12 WattsD. 15 Watts

A ramp is a ___________ that decreases the force required to move and object while increasing the distance the object travels.

A. forceB. loadC. newtonD. machine

What is the Mechanical Advantage of a ramp 2 m long and .5 m tall?A. 1B. 2.5C. 4D. None of the above

Lifting a car using a car jack is easier because it requires ___A. Less forceB. Less workC. Both A and BD. None of the above

At the top of its arc, a thrown ball has ____ potential energy.A. maximumB. minimumC. zeroD. average

As a dropped penny falls toward the ground, ___ energy is converted to ___ energy.

A. thermal, potentialB. kinetic, vibrationalC. kinetic, heatD. potential, kinetic

A dropped racquetball will not return to its original position because

A. potential energy is inefficientB. the mechanical energy is

stored up for later bouncesC. some of the mechanical

energy is converted to nonmechanical energy

D. energy is not conserved

The law of conservation of energy states that energyA. is created from motionB. cannot be created or

destroyedC. is always equal and oppositeD. can only be converted into

heat

_____ is the ratio of useful work output to work input.A. Potential energyB. EfficiencyC. Kinetic energyD. Power

How efficient is a machine that uses 130 J to lift a 50 N load 2 m?A. 19%B. 52%C. 77%D. 87%

__ is a measure of the ability to do work.A. PhotosynthesisB. PowerC. RespirationD. Energy

When a pitcher throws a softball to a catcher, the vibration of the individual atoms that make up the softball is considered ___ energy, while the motion of the ball toward the catcher is considered __ energy.

A. nonmechanical, mechanicalB. potential, nonmechanicalC. electrical, thermalD. mechanical, chemical

What are the two families of simple machines?A. wedge and compoundB. first class and second classC. inclined plane and leverD. pulley and screw

A wedge is a modified __.A. wheel and axleB. pulleyC. inclined planeD. lever

A ramp is a simple machine that allows one to apply an input force __ the output force.

A. perpendicular toB. equal toC. greater thanD. less than

Which of the following is an example of a compound machine?A. scissorsB. ax bladeC. wheel and axleD. screw

What is the mechanical advantage of a single, fixed pulley?A. 0.5B. 1C. 2D. 4