Equations To Learn For Physics GCSE Exam

Question 1

Equation for Work Done

Answer 1

Work Done (Energy Transferred) = Force x Distance

Joules = Newtons x Meters

W = Fxd
J=Nxm

Question 2

Equation for Gravitational Potential Energy

Answer 2

Gravitational Potential Energy = Weight x Change in Height

Joules = Newtons x Meters

Or

Gravitational Potential Energy = Mass x Gravitational Field Strength x Change in Height
Joules = Mass x Newton/Kg x Meters

Question 3

Kinetic Energy Equation

Answer 3

Kinetic Energy = 1/2 x mass x velocity^2

Joules = 1/2 x kilograms x m/s

Question 4

Equation for Efficiency

Answer 4

Efficiency = (Useful Output Energy / Total Input Energy) x 100

Question 5

Equation for Power (Using Energy Transferred and Time Taken)

Answer 5

Power = Energy Transferred/ Time

Watts = Joules / Seconds

Question 6

Equation for Density

Answer 6

Density = Mass / Volume

Density = Kg / Meters^3

Question 7

Equation for Moments

Answer 7

Moment = Force x Distance

Newton Meters = Newtons x Meters

Question 8

Equation for Moments in Equilibrium (The Law of Moments)

Answer 8

F1 x d1 = F2 x d2

Force 1 x Distance 1 = Force 2 x Distance 2

(Clockwise Moments = Anticlockwise Moments)

Question 9

SUVAT equations to learn

Answer 9

Velocity = Displacement / Time (V = s/t)

Acceleration = Final Velocity - Initial Velocity / Time (a = v-u / t)

Question 10

Equation for Resultant Force

Answer 10

Resultant Force = Mass x Acceleration

Newtons = kg x m/s^2

Question 11

Equation for Weight

Answer 11

Weight = Mass x Gravitational Field Strength

Newtons = kg x Newtons/kg

Question 12

Equation for Force Applied to a Spring (Hooke’s Law)

Answer 12

Force Applied to Spring = Spring Constant x Extension

F = kxe

Question 13

Momentum Equation

Answer 13

Momentum = Mass x Velocity

Kg m/s = kg x m/s

Question 14

Equation for Force involving Impact Time

Answer 14

Force = Mass x Change in Velocity / Time Taken

F = m x v / t

Question 15

Equation for Pressure in Solids

Answer 15

Pressure = Force/Area

Pascals = N/m^2

Question 16

Equation for Pressure in Liquids

Answer 16

Pressure = Height x Density x Gravitational Field Strength

Pascals = Meters x kg/m^3 (ρ) x N/kg

Question 17

Equation for Power (Using Current and Potential Difference)

Answer 17

Power = Current x Potential Difference (or Volatge)
(Watts, W) = (Amperes, A) x (Volts, V)

W = I x V

(Another name for potential difference is ‘voltage’)

Question 18

Equation for Power (Using Current and Resistance)

Answer 18

Power = Current^2 x Resistance
(Watts, W) = (Amperes, A) x (Ohms, Ω)

W = I^2 x R

Question 19

Charge Flow (or just Charge) Equation

Answer 19

Charge Flow = Current x Time
(Colombus, C) = (Amperes, A) x (Seconds S)

Q = I x T

Question 20

Equation for Potential Difference or Volatge

Answer 20

Potential Difference = Energy Transferred / Charge
(Volatge, V) = (Joules, J) / (Colombus, C)

V = E / Q

Question 21

Equation for Resistance

And therefore the Equation for Current

Answer 21

Resistance = Potential Difference / Current
(Ohms, Ω) = (Voltage, V) / (Ampere, A)

R = V / I

Current = Potential Difference / Resistance
(Ampere, A) = (Voltage, V) / (Ohms, Ω)

I = V / R

Question 22

Wave Speed Equation

Answer 22

Wave Speed = Frequency x Wavelength
(M/s) = Hertz, Hz) x (Meters, M)

V = f x λ

Question 23

Ultrasound Equation

Answer 23

Depth of Boundary Below Surface = 1/2 x Speed of Wave x Time Taken
(Distance, m) = 1/2 x (m/s) x (Seconds, s)

(s = 1/2 vt)

(The reason we 1/2 it is because the wave travels there and back!)

Question 24

Equation for Magmification

Answer 24

Magnification = Image Height / Objcet Height