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Questions on Forces

Q2.

(a) Megan's dog is pulling on his lead. Which arrow, A, B, C or D, shows the direction of this force?

B

1 mark

(b) Megan has to pull to keep the dog still. Which arrow shows the direction of this force? Give the letter.

D

1 mark

(c) Suddenly the dog's collar breaks.

(i) When the collar breaks, the lead moves. Draw an arrow on the diagram to show which way the lead starts to move.

When the lead breaks there is no longer a balance of the forces to the left and right acting on the lead to keep it taut. There is therefore a net force to the left.

There is also the force of gravity acting on the lead - it will therefore 'fall' - and the net force will be dorn and to the left.

See diagram for the arrow pointing to the left. The arrow may be anywhere on the diagram. Accept arrows pointing diagonally downwards and to the left, but do not accept arrows pointing vertically downwards.

1 mark

(ii) Why does the lead move when the collar breaks?

Answers should refer to a force pulling or the effect of pulling.

Any one from

  • because Megan is still pulling it
  • because there is still a force on acting on it to the left
  • because the forces are now unbalanced ( force D is still acting)

Accept 'because it was stretched' or 'because the dog isn't pulling it any more'

Accept answers referring to gravity, weight or falling only if the candidate has shown the arrow in (c) (i) pointing diagonally or vertically downwards

No marks should be given for 'it is not attached to the dog any more'

1 mark

Maximum 4 marks