Potential Energy and Kinetic Energy Problems PE = mgh KE = 1/2mv2 5 points each (2 points for works, 2 points for correct answer, and 1 point for unit) Use 10 m/s for g 1. A 5 kg ball is lifted from the floor to a height of 1.5 m above the floor. What is the ball's potential energy once it's lifted? 2. An 8 kg ball is moving at 4 m/s. Work is done on the ball to give it a speed of 12 m/s. a. What is the ball's initial kinetic energy? b. What is the ball's final kinetic energy? c. What work was done on the ball? Work = Change in KE Change in KE = KE, - KE; 3. A 3 kg object falls from a height of 10 m. What is its velocity just before it hits the ground? HINT: (top) (bottom) PE + KE = PE + KE mgh + 1/2 mv2 = mgh + 1/2 mv2 mgh + OJ = OJ + 1/2 mv2 2mgh = v2 m Make sure to take the square root4. For the drawing shown, find the following at each point: The object's mass is 10 kg. A: PE= Etotal I KE= C: PE= Etotal KE= 15 m 8 m B: PE= Etotal KE= SHOW all work. Highlight your answers! A. TOP the highest point before the coaster starts PE = KE = Total Energy =. PE + KE Total Energy = V = B. Very BOTTOM ...Hint: Greatest velocity PE = KE = Total Energy =. PE + KE Total Energy = V =C. TOP of second hill PE = KE = Total Energy =. PE + KE Total Energy = V =