Question

With an average acceleration of –0.5 m/s2, (a) how long will it take a cyclist to bring a bicycle with an initial velocity of +13.5 m/s to a complete stop? (b) Calculate the distance required for the bicyclist to come to rest. (c) If the cyclist’s initial speed is doubled to 27 m/s under the same condition, calculate the distance required for the cyclist to come to a halt.

Answer 1

(a) time = velocity / acceleration

(b) distance = average velocity * stopping time
... average velocity = initial velocity / 2 ... final velocity is zero

(c) doubling the speed will double the average velocity
... it will also double the stopping time
... so the stopping distance is quadrupled