P2 2

P2 2.1

If an object stays still - no energy is transferred.
If an object moves in the same direction as the force that is pushing or pulling the object - energy is transferred.
Work done - Energy transferred
- Formula - W = F x d
  - W - work done (J)
  - F - force applied (N)
  - d - distance moved (m)
- 1 joule = 1 newton metre
Energy is never destroyed or created but it can be changed from one form to another.
Friction between moving objects causes heating.

P2 2.2

Power - The amount of energy transferred per second (W) or the rate at which energy is transferred.
- when 1 joule is transferred in 1 second the power is 1 Watt.
Power stations transform chemical energy from fossil fuels into electrical energy.

P2 2.3

Any two masses will attract each other - all masses exert a gravitational pull on all other masses.
Force of gravity - The attraction between objects on or near the earth and the earth itself.
Work done against gravity = downward force (weight of object) x distance lifted.
Energy transferred is stored as gravitational potential energy.
- Formula - Ep = m x g h
  - Ep - potential energy (J)
  - m - mass (kg)
  - g - gravitational field strength (N/kg)
  - h - height change in metres
Kinetic energy - energy due to movement.
- formula - Ek = (0.5mv) x (0.5mv)
  - Ek - kinetic energy (J)
  - m - Mass (kg)
  - v - speed (m/s)

P2 2.4

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