Question

A motor cyclist travelling at 10 ms-1 decelerates at 2 ms-2.(a) How long does he take to come to rest?(b)How far does he travel in coming to rest?

Answer 1

Answer:

Explanation:

Formula

a = (vf - vi)/t

Givens

a = -2 m/s^2   Note, he is decelerating so the number must indicate he's slowing down. That's why it is minus.

vi = 10 m/s

vf = 0

Solution

-2 m/s^2 = (0 -  10)/t

-2 m/s^2 = -10 /  t                     Multiply both sides by t

-2 m/s^2 * t = - 10 m/s /           Divide by - 2

t = -10 / - 2

t = 5 seconds.