# P4 forces

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## Forces

Forces can...

• Affect speed (speed up or slow down)
• Make things change direction
• Make an object change it's shape

Force- a strength or energy as an attribute of physical action or movement

Measured in Newtons (N)

force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When theinteraction ceases, the two objects no longer experience the force. Forces only exist as a result of an interaction.

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## Contact and Non Contact forces

Contact- a force that acts on a point of contact between two objects

• Frictional force
• Tension force
• Air resistance force
• Applied force

Non-contact- A force exerted on another object that is not in contact.

• Gravitational force
• Magnetic force
• Electric force
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## Friction

Friction- an opposing force to a moving object.

The larger the surface area the more the friction

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## Equations

acceleration  =  change in velocity / time taken

velocity  =  distance travelled / time taken

momentum  =  mass x velocity

work done  =  force x distance

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