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GCSE Questions: Forces

Q27. The diagram shows Larry on a bicycle.

He is moving at a constant velocity.

(a) Arrows A and B represent the horizontal forces acting on the bicycle and Larry. By choosing from the following:

Air resistance - Friction - Tension - Upthrust

(i) Name the driving force A - Friction

(ii) Name the counter force B - Air resistance

(iii) What is the relationship between force A and force B when the cyclist travels at a constant velocity? They are equal in magnitude (size) and opposite in direction

[4 marks]

(b) Larry applies a force of 150 N to one of the bicycle pedals.

The diagram below shows the distance between the force applied and the pivot.

Calculate the moment about the pivot caused by the force applied to the pedal.

Moment = force x perpendicular distance from the pivot point

Moment = 150 N x 0.24 m

Moment = 36 Nm

[3 marks]

(c) The diagram below shows how the pedal is connected to the back wheel of the bicycle.

Complete the sentence by choosing one of the following as a missing word:

axle - chain - cog

The force from the cyclist pushing down on the pedal is transmitted to the back wheel by the chain.

[1 mark]

(d) This graph shows how Larry's velocity changes during a journey.

(i) Calculate Larry's acceleration in the first 20 seconds of the journey.

Acceleration = Change in velocity/time taken

a = Δv/t

Δv = 5.8 m/s

a = 5.8/20

a = 0.29 m/s2

[4 marks]

(ii) Describe Larry's movement between 30 and 40 seconds of his journey.

Larry is decelerating uniformly.

[2 marks]

(iii) Calculate how far Larry travelled in the 40 seconds.

Distance travelled = area under the graph - see the graph.

Area A - distance travelled = 58 m

Area B - distance travelled = 58 m

Area C - distance travelled = 29 m

Total distance travelled = 145 m

[4 marks]

(e) Larry travels from home to school on his bicycle.

The diagram shows the route he followed.

 

Draw an arrow on the diagram to show his displacement.

Must be a straight line (use a ruler!)

Must have an arrow head pointing from home to school.

[1 mark]

[18 Marks TOTAL]