# Mechanics, Motion and Movement

Brief overview of mechanics motion and movement for AS OCR PE

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• Created on: 17-01-11 12:20

## Linear and Angular motion

Motion is movement

Linear - when a body moves in a straight or curved line with all its parts moving in the same direction at the same speed

e.g. a tobboganist...all parts of the bodya nd toboggan are moving in a straight line

Angular motion - when a body or part of a body moves in a circle about a particular point

e.g.swimmer doing front crawl, angular motion of the arm about the shoulder joint

General motion - a combination of linear and angular motion

e.g. athlete doing the javelin

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## Force - a push or pull that alters the state of mo

A force can perform the following: -

• cause a body at rest to move
• cause a moving body to 1) change direction 2) accelerate 3) deccelerate
• change an objects shape
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## Newtons Laws of Motion

1)Law of inertia - a body continues in a state of rest unless acted upon by an external force

2)Law of acceleration - when a force acts on an object the rate of change of momentum experienced by the object is proportional to the size of the force and takes places in the direction in which the force acts

3) for every action there is an equal and opposite reaction

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## Centre of mass

centre of mass - the point at which the body is balanced in all directions

stability - relates to how difficullt it is to disturb a body fro a balanced position

line of gravity - a line extending from the centre of mass vertically down to the ground

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