This child’s toy is made up of a flexible track and a model car. Fig. 2.1 is a diagram of the toy. At first, the child holds the car still at point A, which is 0.45 m above the horizontal parts of track BC and FG. The car has a mass of 0.12 kg. The child then lets the car go and it moves towards point B. Air resistance and friction between the car and the track are both negligible. The gravitational field strength is 10 N/kg.
(a)[2]
Calculate the change in gravitational potential energy (g.p.e.) of the car from A to B.
(b)[3]
Calculate the speed of the car when it reaches B.
(c(i))[1]
Explain, in terms of energy, why the car does not go past D, which is also 0.45 m above the horizontal track.
(c(ii))[1]
After leaving A, the car goes to B, then C and then D. Describe the motion of the car after it reaches D.
Worked solution & mark scheme
This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: “change in g.p.e. = mgh OR use 0.12 \times 10 \times 0.45” …