Section 4 - Kinetic And Gravitational Energy

Question 1

Kinetic energy =

Answer 1

1/2 x m x v2

Anything which is moving has kinetic energy. The kinetic energy of something depends both on its mass and speed. The greater its mass and the faster it’s going, the bigger its kinetic energy will be.

Question 2

Gravitational potential energy =

Answer 2

M x g x h

Gravitational potential energy is the energy stored in an object of mass when you raise it to a height against gravity.

You can think of gravitational potential energy as a way of storing kinetic energy.

You have to put work in to move something to increase its gravitational potential energy, and that energy is only released when the object falls.

Question 3

What is the link between gravitational potential energy and kinetic energy?

Answer 3

When something falls, its gravitational potential energy is converted into kinetic energy. So the further it falls, the faster it goes. In practice, some of the gravitational potential energy will be dissipated as heat due to air resistance. But in exam questions they’ll likely say you can ignore air resistance.

Question 4

What is the formula that links kinetic energy and gravitational potential energy?

Answer 4

Kinetic energy gained = gravitational potential energy lost