Physics Unit 9 Work, Power and Energy Test

Kinetic energy is associated with ................ Check all that apply.

• speed

• position

• direction

• movement

• motion

The SI unit of work is ...........

• watt

• newton

• joule

• horsepower

A light plastic cart and a heavy steel cart are both pushed with the same force for a distance of 1.0 m, starting from rest. After the force is removed, the kinetic energy of the light plastic cart is ________ that of the heavy steel cart.

• greater than

• equal to

• less than

• cannot be determined as the weights of each device are not specified

A rock has 10 J of potential energy on top of a roof. If it is dropped and lands with only 8 joules of kinetic energy, how much work did air resistance do on the rock?

• 2 J

• 8 J

• -8 J

• -2 J

In the equation PE = mgh, what does the “g” mean?

• Acceleration due to gravity

• Force of gravity

• Weight of the object

• Acceleratiion due to height

What is the SI unit for power?

• horsepower

• watt

• joule

• newton

Suppose a cart has a kinetic energy of 0.5 J. If you add enough mass to double the mass and make the cart go three times as fast, its kinetic energy is now .............. Be sure to show all your work to get any credit for this problem.

• 6 J

• 3 J

• 18 J

• 9 J

Renatta Gass is out with her friends. Misfortune occurs and Renatta and her friends find themselves getting a workout. They apply a cumulative force of 1080 N to push the car 218 m to the nearest fuel station. Determine the work done on the car. Be sure to show all your work to get any credit for this problem.

• 2.35 x 10⁵ J

• 2.05 x 10⁵ J

• -2.35 x 10⁵ J

• 3.25 x 10⁵ J

A crane lifts an 8-m long steel girder weighing 2600 N up 15 m off the ground. The crane did ___ of work. Be sure to show all your work to get any credit for this problem.

• 120 J

• 39000 J

• 20800 J

• 2600 J

Potential energy is associated with ................ Check all that apply.

• speed

• position

• direction

• vertical height

• elevation