Describe four energy changes that happen in the process.

Driving a motor

chemical energy is converted into kinetic energy.

Falling off of cliff

gravitational potential energy is converted into kinetic energy.

Hydroelectric energy generation

gravitational potential energy is converted into kinetic energy (i.e. driving a generator), which is then converted into electrical energy.

Nuclear power generation

mass is converted into energy, which then drives a steam turbine, which is then converted into electrical energy.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.