Fig. 2.1 shows a man pushing a heavy box with a force P. A frictional force F acts in a horizontal direction. [Figure 2.1]

1. (a)(i)State what is meant by balanced forces.[1]
2. (a)(ii)The frictional force in Fig. 2.1 does not produce any heating effect. State what must happen for the frictional force to produce heating.[1]
3. (a)(iii)Apart from being stationary, describe one other possible state of motion of the box when the forces are balanced.[1]
4. (b)When P = 100 N and F = 85N, the box accelerates. The mass of the box is 25 kg. Calculate the acceleration of the box. acceleration = ................................................................[3][3]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.