A 56 kg student runs up a 3.8 m high stairway in a time of 3 seconds. How many watts of power did she develop? What is the kinetic energy (in Joules) of a 3,330 kg car moving at 95 km/h? What is the gravitational potential energy of a 4.3 kg book lifted and placed on top of a 1.73 m high shelf? A 3.2 kg book lifted and placed on top of a 1.67 m high shelf. What is the speed with which the book hit the ground, if the book falls off the shelf