# AQA Unit 4 Physics Definitions

- Created by: Joe
- Created on: 13-12-12 19:30

Section 1 - Further Mechanics

Newton’s 2nd Law - The rate of change of momentum is directly proportional to the resultant force which acts upon it.

The Newton - One newton is the force that will give a mass of one kilogram an acceleration of one metre per second.

Linear Momentum - The mass of an object multiplied by its velocity.

Conservation of Momentum - In any direction, in the absence of external forces the total momentum of a collision remains constant.

Impulse - Change in momentum of a body.

Elastic Collision - No momentum of kinetic energy is lost.

Inelastic Collision - Momentum is conserved but kinetic energy is lost.

Radian - One radian is the angle subtended at the centre of a circle by an arc of length equal to the circles radius.

Period - The period of an object in circular motion is the time taken for it to complete one revolution.

Angular Speed - The unit angle an object rotates through per unit time.

Centripetal Force - A force which keeps the object moving in a circle.

Simple Harmonic Motion - An oscillation in which the acceleration is inversely proportional to the displacement from the mid-point, and is directed towards the mid-point.

Damping - When energy is lost to the surroundings and the amplitude of an oscillation is reduced.

Resonance - When the driving force equals the natural frequency and causes the…

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