💪 Deck 3 — GPE, KE & Work Done

Gravitational Potential Energy (GPE)

Energy gained when an object is raised above the Earth.

Formula for GPE

Eₚ = mgh.

m in Eₚ = mgh

Mass (kg).

g in Eₚ = mgh

Gravitational field strength (N/kg).

h in Eₚ = mgh

Height (m).

Relationship Between GPE and Work Done

GPE is equal to the work done lifting an object.

Kinetic Energy (KE)

Energy due to motion.

Formula for KE

Eₖ = ½mv².

m in Eₖ = ½mv²

Mass (kg).

v in Eₖ = ½mv²

Speed (m/s).

Work Done

Work is done when a force moves an object through a distance.

Formula for Work Done

W = Fd.

F in W = Fd

Force (N).

d in W = Fd

Distance moved in the direction of the force (m).

One Joule of Work

1 J is done when a force of 1 N moves an object 1 m in the direction of the force.

Example Where Work Is Done

Climbing stairs.

Example Where No Work Is Done

Pushing a wall that does not move.

Another Example Where No Work Is Done

Carrying a box horizontally.

When Is No Work Done?

When the object does not move or the force is perpendicular to the direction of motion.

Effect of Friction on Energy

Friction transfers energy to the internal (thermal) energy store.