A Star GCSE Combined Science – Formula Drill

Write the equation for speed.

speed = distance / time; v = d / t. Unit: m/s.

Rearrange v = d/t to find distance.

d = v x t.

Write the equation for acceleration.

acceleration = change in velocity / time; a = Δv / t. Unit: m/s².

Velocity changes from 6 m/s to 18 m/s in 3 s. Find acceleration.

Δv = 18 - 6 = 12 m/s; a = 12 / 3 = 4 m/s².

Write the equation linking force, mass and acceleration.

F = m x a. Force: N; mass: kg; acceleration: m/s².

Rearrange F = ma to find acceleration.

a = F / m.

Write the equation for weight.

W = m x g. Weight: N; mass: kg; g: N/kg.

What is g in W = mg?

Gravitational field strength. Unit: N/kg.

Write the equation for pressure.

P = F / A. Pressure: Pa; force: N; area: m².

Rearrange P = F/A to find force.

F = P x A.

Rearrange P = F/A to find area.

A = F / P.

600 N acts over 0.04 m². Find pressure.

P = 600 / 0.04 = 15,000 Pa.

Write the equation for kinetic energy.

KE = ½mv². Energy: J; mass: kg; velocity: m/s.

A 5 kg object travels at 4 m/s. Find kinetic energy.

KE = ½ x 5 x 4² = 40 J.

Write the equation for gravitational potential energy.

GPE = mgh. Energy: J.

What do m, g and h mean in GPE = mgh?

m = mass (kg); g = gravitational field strength (N/kg); h = height (m).

Write the equation for work done.

W = F x d. Work: J; force: N; distance: m.

Rearrange W = Fd to find force.

F = W / d.

Write the equation for power using energy and time.

P = E / t. Power: W; energy: J; time: s.

12,000 J is transferred in 30 s. Find power.

P = 12,000 / 30 = 400 W.

Write Ohm's law.

V = I x R. V = volts; I = amperes; R = ohms.

Rearrange V = IR to find current.

I = V / R.

Rearrange V = IR to find resistance.

R = V / I.

12 V is applied across a 40 ohm resistor. Find current.

I = 12 / 40 = 0.3 A.

Write the equation for charge transferred.

Q = I x t. Charge: C; current: A; time: s.

0.5 A flows for 40 s. Find charge transferred.

Q = 0.5 x 40 = 20 C.

Write the electrical power equation.

P = V x I. Power: W; voltage: V; current: A.

Rearrange P = VI to find current.

I = P / V.

Write the wave speed equation.

v = f x λ. v = m/s; f = Hz; λ = m.

Frequency = 50 Hz and wavelength = 2.4 m. Find wave speed.

v = 50 x 2.4 = 120 m/s.

Write the equation linking period and frequency.

T = 1 / f. Period: s; frequency: Hz.

Rearrange T = 1/f to find frequency.

f = 1 / T.

Write the percentage efficiency equation.

Efficiency = useful output / total input x 100.

500 J input; 350 J useful output. Find efficiency.

350 / 500 x 100 = 70%.

Write the percentage change equation.

(new - original) / original x 100.

A plant grows from 20 cm to 26 cm. Find percentage increase.

Change = 6 cm; 6 / 20 x 100 = 30%.

A question gives force and area and asks for pressure. Which equation?

P = F / A.

A question gives voltage and resistance and asks for current. Which equation?

Start with V = IR; rearrange to I = V / R.

A question gives initial velocity, final velocity and time. Which equation?

a = (final velocity - initial velocity) / time.

A question gives current and time and asks for charge. Which equation?

Q = I x t.

What unit is used for energy and work done?

joule (J).

What unit is used for power?

watt (W). 1 W = 1 J/s.

What units are used for current and charge?

Current = ampere (A); charge = coulomb (C).

What units are used for pressure and acceleration?

Pressure = pascal (Pa); acceleration = m/s².

Convert 4.7 kPa to Pa.

4.7 kPa = 4700 Pa. kilo = x1000.

Convert 3500 mg to g.

3500 mg = 3.5 g. 1000 mg = 1 g.