A-LevelMathematicsMechanics9709/43 · Oct/Nov 2019 · Q46 Marks
A car travels along a straight road with constant acceleration. It passes through points P, Q, R and S. The times taken for the car to travel from P to Q, Q to R and R to S are each equal to 10s. The distance QR is 1.5 times the distance PQ. At point Q the speed of the car is 20ms⁻¹.
- (i)Show that the acceleration of the car is 0.8 ms⁻².[3]
- (ii)Find the distance QS and hence find the average speed of the car between Q and S.[3]
Mark scheme
Marking points from the official mark scheme (Oct/Nov 2019). The mark or mark type is shown in brackets.
- [M1] For use of s = vt - (1/2)at² or s = ut + (1/2)at² suvat to find PQ or QR
- [A1] OE (s = 200-50a and 1.5s = 200 + 50a)
- [B1] AG (1.5(200 – 50a) = 200 + 50a → 100 = 125a → a = 0.8 ms⁻²)
- [M1] Using s = ut + (1/2)at² OE
- [A1] Distance=560 m
- [B1] Average speed between Q and S = 560/20 = 28ms⁻¹
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