HideShow resource information

Working Hard!

work is done and energy is transferred whenever a force moves

Equation For Work Done:   Work Done(J) = Force (N) x Distance moved in direction of force (m)

EXAMPLE: A person lifts a 60n parcel by 1.5m. work done is 60N x 1.5m = 90J

A smaller force is needed to drag something up a ramp compared with lifting it directly up. the force along the ramp is working over a long distance, and also needs to work against friction.

Remember! the force must move in order to do work. A person lifting a box does work but when he is just standing with the box he is doing no work because he is not moving.

1 of 3

Gravitational Potential Energy!

Gravitational energy is energy an object has due to its position.The object gains more energy when it is lifted higher above the ground 

Equation: Gravitational Potential Energy (joules) = mass (Kg) x Gravity (10N/Kg) x Height (m) 

EXAMPLE: The gravitational potential energy gained by a 3kg rabbit lifted 0.8m by its owner is; 3 x 10 x 0.8 = 24J

2 of 3

Investigating Kinetic Energy!

All moving objects have kinetic energy, Kinetic energy is calculated using:

  • Kinetic energy (J) = 1/2 x mass (kg) x velocity(squared) (M/S) 
  • EXAMPLE: Kinetic energy of a person (mass 100Kg) running at 3 m/s is 1/2 x 100 x 3(squared) -450J

The Kinetic energy of an object:

  • doubles if mass doubles
  • quadruples if the speed doubles 

At its highest point, a pendelum has a gravitational energy and no kinetic energy, as it swings down some gravitational energy changes to kinetic energy and back again!


3 of 3


No comments have yet been made

Similar Science resources:

See all Science resources »See all Energy and efficiency resources »