A5 kilogram cat is resting on top of a bookshelf that is 3 meters high. what is the cat’s gravitational potential energy relative to the floor?

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.