Physics calculations are some of the easiest marks on the paper, if you follow a clear routine. Most lost marks come from wrong units or messy rearranging, not from hard physics.
Step 1: learn the equations
Your exam board lists the equations you must remember and those you are given on an equation sheet. Check your board's list. Learn the "recall" ones with flashcards: equation on one side, words and units on the other.
For example: speed = distance ÷ time, in m/s = m ÷ s.
Step 2: use a set routine
For every calculation, write:
- The equation in symbols or words.
- The values from the question, with units.
- Convert units if needed.
- Rearrange (if needed).
- Substitute the numbers.
- The answer, with the unit.
Writing each step can earn marks even if the final answer is wrong.
Step 3: convert units first
Common conversions:
| From | To | Do this |
|---|---|---|
| km | m | × 1000 |
| g | kg | ÷ 1000 |
| minutes | seconds | × 60 |
| kJ | J | × 1000 |
| cm | m | ÷ 100 |
| mA | A | ÷ 1000 |
Step 4: rearrange with confidence
Treat it like a Maths equation: do the same to both sides.
Example: Rearrange P = E ÷ t to find E.
Multiply both sides by t: E = P × t.
Example: Rearrange Ek = ½mv² to find v.
Divide by ½m: v² = 2Ek ÷ m, then square root: v = √(2Ek ÷ m).
If you find rearranging hard, put the numbers in first, then solve the simple equation.
Step 5: check the answer
- Does the size make sense? A car does not travel at 3000 m/s.
- Did you give the unit?
- Did you round as the question asks (for example, to 2 significant figures)?
In short
Learn the equations, use the same six-step routine every time, convert units first and always give a unit. Physics calculations then become reliable marks.
Notes, tests and papers for your exam board
AshACE® Revise is opening soon for Year 6 to GCSE.