Question

The rock is released from rest at point 0. Derive an expression for the speed with which the rock crashes into a planet.

Answer 1

Answer:

When a rock falls from rest on planet at a height above the surface, the rock accelerates due to the gravitational acceleration near the planet's surface. We model the motion as straight-line constant-acceleration motion. An alternative way to analyse this is using energy methods where the gain in kinetic energy as the rock falls equals the loss in gravitational potential energy.

Explanation:

The speed of the rock is constantly changing since the motion is straight-line constant acceleration motion.