A roller coaster consists of carts has a mass of 200 kg. A - What is the velocity of the cart at the bottom of the roller coaster if it has a kinetic energy of 160 000J?

B - If 20% of the energy was wasted as heat and sound when the cart rolled down the roller coaster, what was the total gravitational potential energy that the roller coaster started with (g=9.81 N/kg)?

C - What was the height at the top of the roller coaster?

D - If the roller coaster cart gained this gravitational potential energy through a pulley system with a motor, and the motor took 30 seconds to pull the cart from the bottom to the top what was the power of the motor?