Forces - Section B - Maths questions

Don’t forget to take a ruler and calculator into the exam.

Maths questions often start with the command words like 'calculate', 'determine', 'estimate' and 'measure'. They will then include blank space for you to show your working.

When an answer to a maths question is marked:

  • full marks are given for the right answer (but it’s wise to show your working so you can check your answer)
  • marks are given for working, including substitution and rearrangement
  • errors carried forward are taken into account

Errors carried forward are related to what happens if a later answer depends on an earlier answer, and you get the earlier one wrong. You could still get full marks in the later answer if your working is correct but you use the incorrect earlier answer.

If your answer has many decimal places or figures, make sure you give it to an appropriate number of decimal places or significant figures. You may be asked to give units. This may earn you an additional mark, so don’t forget to check whether you need to do this.

Some maths questions might ask you to plot or complete a graph or table. When you draw a graph, make sure you:

  1. Plot each point accurately.
  2. Draw a best fit straight line or curve.

You may be given a grid with axes and scales already given. Sometimes you may be given an empty grid for you to supply your own axes. When you do this:

  • put the independent variable on the x-axis and the dependent variable on the y-axis
  • make sensible scales so that the plotted points cover at least 50% of the area of the graph

Label the axes with their quantity and unit, eg time (s).

Sample question 1 - Foundation

Question

A toy train travels for 45 seconds at 2 m/s.

Calculate the distance it travels. Show your working. [4 marks]

OCR Gateway Science, GCE Physics, Paper J249, 2016.

speed = distance ÷ time

rearrange: distance = speed × time

distance = 2 × 45

= 90 m

Sample question 2 - Foundation

Question

Four students investigate the idea of work done.

work done = force × distance

Look at their results.

Student Force (N) Distance travelled (m)
A1005
B5010
C12012
D404

a) Use calculations to show which student does the most work. [2 marks]

b) Which two students do the same amount of work? [1 mark]

OCR Gateway Science, GCE Physics, Paper J249, 2016.

a) Student C

Calculations:

work = force × distance

work done by student A = 100 × 5 = 500 J

work done by student B = 50 × 10 = 500 J

work done by student C = 120 × 12 = 1,440 J

work done by student D = 40 × 4 = 160 J

b) Students A and B

(A = 500 J, B = 500 J, C = 1,440 J, D = 160 J)

Sample question 3 - Higher

Question

A 0.25 kg glider is pulled by a 1.0 N force.

Calculate the acceleration of the glider using the formula. [1 mark]

OCR Gateway Science, GCE Physics, Paper J249, 2016 - Higher.

1.0 ÷ 0.25

= 4 m/s2

Sample question 4 - Higher

Question

Two ice skaters, A and B, at rest, start together on the ice.

Skater A has a mass of 60 kg and skater B has a mass of 90 kg.

The skaters push apart and move off in opposite directions. Skater B travels at 2 m/s.

Use the data and your knowledge of momentum to calculate the velocity of skater A after pushing. [2 marks]

OCR Gateway Science, GCE Physics, Paper J249, 2016 - Higher.

(60 × velocity) + (90 × 2) = 0

velocity = 180 ÷ 60

= 3 m/s