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Directions: For each situation, you need to determine if the object has KE or GPE or both. Then find their values. Be sure to include the correct units.

  1. A 2-kg bowling ball sits on top of a building that is 40 meters tall.

Circle one: KE / GPE / both


Show your work for finding the values of each type of energy the object has:




  1. A 2-kg bowling ball rolls at a speed of 5 m/s on the roof of the building that is 40 tall.

Circle one: KE / GPE / both


Show your work for finding the values of each type of energy the object has:



  1. A 2-kg bowling ball rolls at a speed of 10 m/s on the ground.

Circle one: KE / GPE / both


Show your work for finding the values of each type of energy the object has:



  1. A 20-kg child is tossed up into the air by her parent. The child is 2 meters off the ground traveling 5 m/s.

Circle one: KE / GPE / both


Show your work for finding the values of each type of energy the object has:














Part 2: Finding Speed and Height Using Energy


Directions: Use the KE and GPE equations to solve for speed or height depending on the situation.

  1. A 1,000-kg car has 50,000 joules of kinetic energy. What is its speed?


  2. A 200-kg boulder has 39,200 joules of gravitational potential energy. What height is it at?


  3. A 1-kg model airplane has 12.5 joules of kinetic energy and 98 joules of gravitational potential energy. What is its speed? What is its height?

Verified Answer :

  1. A 2-kg bowling ball sits on top of a building that is 40 meters tall. Circle one: KE / GPE / both Show your work for finding the values of each type of energy the object has:

    KE = 0 (because velocity is 0)

    PE = mgh = 2kg9.8m/s^240m= 784 joule

    2. A 2-kg bowling ball rolls at a speed of 5 m/s on the roof of the building that is 40 tall. Circle one: KE / GPE / both Show your work for finding the values of each type of energy the object has:

    Both
    KE = [1/2]mv^2 = [1/2](2kg)(5m/s)^2 =  25 joul
    PE = mgh = 40 joule

    3. A 2-kg bowling ball rolls at a speed of 10 m/s on the ground. Circle one: KE / GPE / both Show your work for finding the values of each type of energy the object has: 

    KE = [1/2]m(v^2) = [1/2]2kg    (10m/s)^2 = 100 joule

    GPE = mgh = 0

    1. A 1,000-kg car has 50,000 joules of kinetic energy. What is its speed?

    KE = [1/2]m(v^2) => v = √[2KE/m] = √[250,000joules/1000kg] = 10m/s

    2. A 200-kg boulder has 39,200 joules of gravitational potential energy. What height is it at? 

    GPE = mgh => h = GPE / (mg) = 39,200 joules / (200kg     9.8m/s^2) = 20m


    3. A 1-kg model airplane has 12.5 joules of kinetic energy and 98 joules of gravitational potential energy. What is its speed? What is its height?

    KE = [1/2]m(v^2) => v = √ [ 2KE/m] = √[212.5 j / 1kg] = 5 m/s

    GPE = mgh => h = GPE/(mg) = 98/(1kg    9.8m/s^2) = 10 m

    Sorry I don't know number 4 for part 1

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