# P3 Forces,Speed,Kinetic Energy and Power

HideShow resource information
• Created by: LukeMinns
• Created on: 23-04-16 17:08

## Forces

Force=Mass x Acceleration

6 Forces alltogether:

• Gravity
• Reaction Force
• Thrust
• Drag (Air resistance)
• Lift
• Tension

Terminal Velocity

When the acceleration is equal to the resistance force that is the terminal velocity. It can also be effected by different things like weight and resistance.

Work Done

When a force makes an object move, energy is transferred and work is done

Work done=Force x Distance

1 of 5

## Speed

Distance =Speed x Time

Average speed = (speed at the start + speed at the end) / 2

Acceleration=Change in speed/ Time taken

Velocity tells us direction but speed only tells us how fast it is going

Momentum

Momentum= Mass x Velocity

To work out a change in momentum the formula is

Force Acting (N) = Change in momentum / Time taken for change to happen

2 of 5

3 of 5

## Kinetic Energy

Kinetic Energy = 1/2 x mass x speed

The energy of something when it is moving. The more mass and speed there is, the more Kinetic energy it has

Gravitational Potential Energy (GPE)

GPE= Mass x Gravitational Field Strength (On earth it is 10N/Kg) x Height

Energy is transferred to Kinetic energy when it falls

Once the object hits terminal veloctiy then the KE cannot increase but can lose Kinetic energy through friction and heat loss.

4 of 5

## Power

The rate of doing something e.g. How much energy a machine transfers per second

Power= Work done/ Time taken

Power is measure in J (Joules)

There is also another formula to work out power which is

Power = Force x speed

5 of 5