Ocr Physics A G484 Defintions

Front 1

Newton's 1st Law of Motion

Back 1

An object will remain at rest or continue travelling at a constant velocity, unless acted upon by an external force.

Front 2

Newton's 2nd Law of Motion

Back 2

The change in momentum of an object is directly proportional to the net force acting upon it, and is in the direction of the net force.

Front 3

Newton's 3rd Law of Motion

Back 3

When object A exerts a force on object B, object B exerts a force that is equal, opposite in direction, and of the same type on object A.

Front 4

Impulse

Back 4

The product of the force and the time for which it acts (F∆t). It is equal to the change in momentum of a body (area under a force-time graph).

Front 5

Perfectly Elastic Collision

Back 5

Both kinetic energy and momentum are conserved.

Front 6

Inelastic Collision

Back 6

Momentum is conserved, kinetic energy is not. Due to the objects deforming, kinetic energy is transferred to other forms of energy, such as thermal.

Front 7

Newton

Back 7

The force that gives a mass of 1kg an acceleration of 1ms^-2.

Front 8

Principle of Conservation of Momentum

Back 8

In a closed system, the total momentum before a collision is equal to the total momentum after a collision.

Front 9

Radian

Back 9

The angle subtended at the centre of a circle by an arc length equal to the radius.

Front 10

Angular Frequency

Back 10

Change of angle per unit time.

Front 11

Frequency

Back 11

Number of oscillations per unit time.

Front 12

Period

Back 12

Time taken for a complete oscillation.

Front 13

Displacement

Back 13

Distance an object has travelled from its rest position.

Front 14

Amplitude

Back 14

Maximum displacement of a particle from the equilibrium position.

Front 15

Centripetal Force

Back 15

Net force acting on an objecting causing it to travel in a circular path, and is always directed towards the centre of the circle.

Front 16

Centripetal Acceleration

Back 16

Acceleration towards the centre of a circle keeping the object in elliptical orbit.

Front 17

Gravitational Field Strength

Back 17

Force per unit mass.

Front 18

Newton’s Law of Gravitation

Back 18

Gravitational force of attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

Front 19

Kepler’s 3rd Law

Back 19

The square of the orbital period of a planet is directly proportional to the cube of its orbital radius.

Front 20

Geostationary Orbit

Back 20

An artificial satellite with an equatorial orbit, with the orbital period equal to one day.

Front 21

Phase Difference

Back 21

Fraction of an oscillation between the vibrations oscillating particles.

Front 22

Simple Harmonic Motion

Back 22

An object where its acceleration is proportional to its displacement, in the direction of the equilibrium position.

Front 23

Damping

Back 23

Oscillatory motion where the amplitude is severely reduced due to energy loss.

Front 24

Resonance

Back 24

Where driving frequency is equal or close to the vibrating object’s natural frequency, causing a huge increase in its amplitude.

Front 25

Pressure

Back 25

Force per unit cross-sectional area.

Front 26

Internal Energy

Back 26

Sum of the random distributions of kinetic and potential energies of all the particles in a body.

Front 27

Specific Heat Capacity

Back 27

Energy required per unit mass of a substance to raise its temperature by 1K or 1℃.

Front 28

Latent Heat of Fusion

Back 28

Quantity of energy per unit mass required to change a substance from a solid into a liquid, at a constant temperature.

Front 29

Latent Heat of Vaporisation

Back 29

Quantity of energy per unit mass required to change a substance from a liquid into a vapour, at a constant temperature.

Front 30

Boyle’s Law

Back 30

The volume of a fixed mass of gas is inversely proportional to the pressure exerted on it, provided the temperature is kept constant.

Front 31

Charles’ Law

Back 31

The volume occupied by a gas at constant temperature is directly proportional to its absolute temperature.