Question Constellation Sign up for free AQA · GCSE · Combined Science · Higher
Forces and motion of the man
Figure 10 shows the horizontal forces acting on a man swimming in the sea.
The man increases Force A.
Explain what happens to Force B and to the movement of the man.
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Marking points
- 1 State that the man accelerates when Force A is increased.
- 2 State that Force B increases.
- 3 Explain that Force B increases until it equals Force A, so the resultant force becomes zero again.
- 4 State that the man then moves at a higher constant velocity.
Full-mark answer
When Force A is increased, the man accelerates. As he moves faster, Force B increases until it is equal to Force A, so the resultant force becomes zero. The man then moves at a higher constant velocity.
Why this answer loses marks
Force B stays the same and the man keeps accelerating.
The mark scheme requires Force B to increase and eventually balance Force A, giving a higher constant velocity.