Mechanical Energy KE = 1/2 mv2, PE = mgh 1. A car has a mass of 1200 kg. Find the kinetic energy at the following speeds a) 10 m/s b ) 20 m/s c) 30 m/s d) 54 km/h 3. A rollercoaster car has a mass of 1500 kg including the riders. Find the kinetic, potential and total mechanical energy at the following heights and speeds a) 25 m, 3.5 m/s, b) 2.5 m, 22 m/s 4. Find the velocity of a 60 kg runner with a kinetic energy of 750 Joules 5. Find the height of a 6.0 kg object that has a potential energy of 882 Joules 6. A 5.0 kg object is dropped from a height of 35 m. a) find the potential energy b) assuming energy is conserved, find the kinetic energy just before it hits the ground c) using the kinetic energy you found in b, calculate the velocity 7. A 2.0 kg rock is thrown upward from ground level with an initial upward velocity of 15 m/s. a) Find the kinetic energy of the rock b) assuming no energy is lost, find the potential energy of the rock at its maximum height (hint it will have no kinetic energy at that height) c) Find the maximum height 8. A rollercoaster car with a mass of 1000 kg starts at a height of 26 m. a) find the potential energy b) assuming energy is conserved, find the kinetic energy when it reaches ground level c) using the kinetic energy you found in b, calculate the velocity at ground level