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Q5. Sarah made a cotton reel vehicle like the one shown in the diagram. The pencil is wound round and round so that it winds up the rubber band. A piece of candle wax next to the cotton reel lets the rubber band slowly unwind.

(a) As the rubber band unwinds, the candle wax slips and the cotton reel turns. Name the force which acts between the cotton reel and the candle wax.

Friction

1 mark

(b) Sarah tested the vehicle by letting it run along a horizontal table top.

(i) She noticed that the vehicle gradually slowed down. Give the reason for this.

any one from

  • energy stored in the rubber band gets less as it unwinds and becomes less stretched
  • the tension in the rubber band decreases as it unwinds
  • the force exerted by the rubber band gets less as it unwinds

1 mark

(ii) Describe what Sarah could do to make the rubber band move this vehicle faster.

She should twist the rubber band more times so there are more turns of it.

1 mark

Maximum 3 marks