# Mechanics Definitions: OCR AS Physics A

A collection of all of the definitions needed for the mechanics paper, taken from all of the available past papers and some textbooks too.

- Created by: Charlotte!
- Created on: 26-04-12 19:48

First 189 words of the document:

Mechanics

Acceleration

Rate of change of velocity a=(v-u)/t

Braking Distance

Distance travelled by the car between the time of the brakes being applied

and the car stopping

Brittle Material

Does not have a plastic region, breaks at elastic limit

Centre of Gravity

The point where an object's entire weight appears to act

A Couple

A pair of equal and opposite forces separated by a distance

Density

The mass per unit volume =m/V

Elastic Limit

The point after which a material does not return to its original form when

stress is removed

Equilibrium

Net force acting on the object must be 0, net moment about any point must

also be zero

Hooke's Law

The extension of a spring is directly proportional to the force applied to it

(within elastic region)

The Joule

The work done moving 1N through 1m in the direction of the force

The Newton

The force required to accelerate 1kg to 1ms-1

Plastic deformation

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