key concepts for physics

Distance

speed × time

Acceleration

(final velocity − initial velocity) ÷ time

Force

mass × acceleration

Weight

mass × gravitational field strength

Change in gravitational potential energy

mass × gravity × change in height

Kinetic energy

½ × mass × speed²

Efficiency

useful energy output ÷ total energy input

Wave speed

frequency × wavelength

Work done

force × distance (moved in the direction of the force)

Power

work done ÷ time = energy transferred ÷ time taken

Moment of a force

force × perpendicular distance from pivot

Energy transferred

charge moved × potential difference

Charge

current × time = Q = It

Voltage (Potential Difference)

current × resistance = V = IR

Electrical power

current × potential difference = P = IV

Density

mass ÷ volume = ρ = m ÷ V

Force on a spring

spring constant × extension = F = kΔx

Pressure

force ÷ area = P = F ÷ A

Momentum

mass × velocity = p = mv