# Forces - Short answer questions

Some short answer questions will be multiple choice questions. These will appear in both exam papers, and at both Tiers. Multiple choice questions are asked as questions, often starting with 'What is …' or 'Which of these …'

You have four options to choose from in a multiple choice question. You must only choose one of these options, by writing your answer (A, B, C, or D) in a box.

It may help to reject any answers that you feel are obviously wrong, so that you can focus on choosing the right answer.

Other short answer questions will start with command words such as 'describe' or 'explain'. Some command words are easy to understand such as:

• 'calculate' or 'determine' for maths questions
• 'complete' to fill in a gap in a table or graph
• 'define' to give the meaning of an important word
• 'suggest' where you use your knowledge in an unfamiliar situation

The command words 'describe' and 'explain' can be confusing. If you are asked to describe a graph, you will be expected to write about its overall shape, whether it is linear or curved, the slope of gradients etc. If you are asked to explain why a pattern or trend is seen in a graph, you will be expected to use your science knowledge, not just say what you see (which is a description), eg 'The graph shows a steep linear increase for the first three hours because…'.

'Explain how' and 'why' questions often have the word 'because' in their answer. 'Describe' questions don't.

The number of marks per question part is given in this form '[2 marks]'. It is essential that you give two different answers if a question is worth two marks. Sometimes you can gain a second mark by giving the units in a calculation or stating specific data points, eg the speed of the object decreased by 8m/s.

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

## Sample question 1 - Foundation

Question

Look at the following gear system and answer the questions.

a) How many teeth has:

i) gear A?

ii) gear B? [1 mark]

b) If gear A turns in an anticlockwise direction which way does gear B turn? [1 mark]

c) If gear A, the driving gear, rotates at 100 revolutions per minute, what is the gear ratio and how fast does gear B rotate? [2 marks]

a) i) 12

ii) 24

b) Clockwise

c) Gear ratio is 2:1, so 50 revolutions per minute.

## Sample question 2 - Higher

Question

This diagram shows a free body force diagram of a large crate being pulled across a floor with a rope:

a) Identify and name the forces A, B, C and D. [4 marks]

b) If the crate moves at a constant velocity what can you say about the horizontal forces? [1 mark]

a)

• A - pull from rope
• B - weight
• C - reaction force
• D - frictional force

b) There is a zero resultant horizontal force, A = D