Another conservation of energy problem

[physicsman2]

Homework Statement

why is the gravitational potential energy of a ball equal to its kinetic energy

Homework Equations

KE=PE

The Attempt at a Solution

im really not sure, i think its because energy is conserved but i don't know why that is either

 

[cybernerd]

Yes, it has to do with the conservation of energy. Think of it this way - If you hold a ball in your hand and drop it, the kinetic energy will equal the gravitational potential energy, because the ball cannot acquire energy from any other source. Gravity is the only thing pulling the ball down - no other force is going to help the ball fall.

 

[physicsman2]

oh i understand now thanks

 

[LowlyPion]

why is the gravitational potential energy of a ball equal to its kinetic energy

As stated it is not.

The conservation of energy tells you however that the Δ in potential energy will manifest as a Δ in kinetic energy when a ball is released in a gravitational field.