Solve the following word problems using the kinetic and potential energy formulas. Be sure to SHOW YOUR WORK!!

KE = PE = ×× = ⁄

Example 1

A group measures the speed of a 0.1 kg car at 2.5 m/s. What is the kinetic energy of the car?

KE = 12 × 0.1 ×(2.52) {When something is square it is multiplied by itself (2.5 x 2.5)

KE = 0.05 ×6.25

KE = 0.3125 Joules

Example 2

You are on rollerblades at the top of a 10 m hill. Your mass is 60 kg. What is your potential energy?

PE = 60 x 10 x 10

PE = 6000 J

1. Determine the kinetic energy of a 1000 kg roller coaster car that is moving with a speed of 20.0 m/s.

2. Missy Diwater a platform diver, had a kinetic energy of 15,000 J prior to hitting the bucket of water. If Missy’s mass is 50 kg, then what is her speed?

3. A cart is loaded with brick and pulled to the top of a ramp. If the mass of the loaded cart is 3.0 kg and the height of the plane is 0.45 meters, what is the potential energy of the loaded cart?

4. A 75 kg refrigerator is located 300 meters above the ground. What is the potential energy of the refrigerator?

5. The potential energy of a 40 kg cannon ball is 14,000 J. How high was the cannon ball to have this much potential energy?