A car is towing a trailer along a straight horizontal road by means of a horizontal tow-rope. The mass of the car is 1400 kg. The mass of the trailer is 700 kg. The car and the trailer are modelled as particles and the tow-rope as a light inextensible string. The resistances to motion of the car and the trailer are assumed to be constant and of magnitude 630 N and 280 N respectively. The driving force on the car, due to its engine, is 2380 N.
Find the acceleration of the car.
Find the tension in the tow-rope.
When the car and trailer are moving at 12 m s-1, the tow-rope breaks. Assuming that the driving force on the car and the resistances to motion are unchanged, find the distance moved by the car in the first 4 s after the tow-rope breaks.
State how you have used the modelling assumption that the tow-rope is inextensible.
2 exam-style questions on Edexcel A Level Old Maths Dynamics - F=ma. Each one has a worked solution and a mark scheme showing where the marks go.