phy

Speed

Distance travelled in unit time.

Acceleration

Change in velocity divided by time taken.

Velocity time graph

Area under graph measures distance travelled.

Distance time graph

Gradient of graph measures velocity.

Newton's First Law

Object stays stationary unless acted upon by some external force.

Terminal Velocity

Weight downwards is equal to air resistance upwards.

Resultant Force

Two unbalanced forces equivalent to one force.

Newton's Second Law

Resultant force equals mass times acceleration.

Newton's Third Law

For every action, there is an equal but opposite reaction.

Momentum

Momentum equals mass times velocity.

Impulse

Change in momentum divided by time.

Centripetal Force

Inward force needed to make an object move in a circle.

Moment of a Force

Turning effect of a force, moment of force equals force times distance.

Condition for Equilibrium

Sum of clockwise moment equals sum of anti-clockwise moment.

Hooke's Law

Extension is proportional to the load if beneath the elastic limit.

Pressure

Force divided by area.

Pressure in Liquids

Pressure equals density times gravity times depth.

Pressure from Air

Instrument to measure atmospheric pressure is a barometer.

Gas Laws

Pressure is inversely proportional to volume for a fixed mass of gas at constant temperature.

Work

Work equals force times distance.

Gravitational Potential Energy (GPE)

GPE equals mass times gravity times height.

Kinetic Energy (KE)

KE equals half times mass times velocity squared.