Question

Two teenagers Sam and Alex are excited to drive for the first time after getting their driving license. Sam and Alex are travelling eastwards on a straight level road. Alex is speeding at 24 m/s ahead Sam. When the distance between them is 100 m, Sam starts from rest, chasing Alex at a constant acceleration of 2.0 m/s². When Sam attains a speed of 40 m/s, Alex starts to slow down because a speed trap is ahead.

(a) Calculate the         

i. Time taken by Sam to reach a speed of 40 m/s? [2 marks]

ii. Position of the Alex relative to the Sam, 15 seconds from the instant Sam started the

chase after him? [3 marks]

iii. The distance Sam travelled before he attained the speed of 40 m/s?   [2 marks]

iv. Distance of Alex from Sam when he spotted the speed trap?   [3 marks]

(b) Sketch the velocity-time curves for Sam’s and Alex’s motion in a same graph. [4 marks]

Answer 1