1.1. A student investigates the relationship between force and acceleration for a trolley on a runway. Figure 12 shows some of the apparatus the student uses.

Figure 12

i) Describe how the student could increase the accelerating force applied to the trolley.

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ii) Describe how the mass of the moving system can be kept constant.

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iii) Explain how the student could improve the procedure to compensate for the effects of frictional forces acting on the trolley.

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1.2. Higher Tier Only

 Figure 13 shows two objects, Q and R, before and after they collide.

Figure 13

The arrows show the direction of movement of the objects.

The arrows are not to scale.

Explain how momentum is conserved in the collision.

Use Newton’s third law and Newton’s second law in your answer. Newton’s second law can be written as

$force=\frac{changeinmomentum}{time}$