Energy

Potential Energy

energy stored by height

Lifting an object stores gravitational potential energy, mass times gravity times height, ready to turn back into motion.

Example

Lifting an object stores energy as gravitational potential energy, mass times gravity times height, ready to turn back into motion.

highlighted = computed this step

Potential energy is stored by height

Lifting something stores energy you can get back later. Gravitational potential energy is mass times gravity times height above the ground.

PE=m g hPE = m\,g\,h
A raised cart stores potential energyA cart resting at the top of a sloped track, high above the ground.m

A worked value

A 2 kilogram cart held 5 metres up has potential energy 2 times 10 times 5, or 100 joules — ready to turn into motion.

PE=m g h=2 kg ⋅ 10 m/s2 ⋅ 5 m=100 JPE = m\,g\,h = 2\ \text{kg} \,\cdot\, 10\ \text{m}/\text{s}^{2} \,\cdot\, 5\ \text{m} = \hl{100}\ \text{J}
mechanics A 2 kg cart 5 m up with g = 10 gives a clean 100 J of stored energy.