Question

A motorcycle traveling at 36 m/s slams on the brakes to avoid an accident. The motorcycle skids 23m before stoping. What is the motorcycle’s acceleration? How long does it take to come to a stop

Answer 1

Since the motor cycle was moving at 36 m/s before the brakes were applied, the initial velocity
$u = 36 {ms}^{ - 1}$
The motorcycle traveled 23m before stopping, that means
$s = 23m$
Since the motorcycle stopped moving the final velocity is zero.

$v = 0{ms}^{ - 1}$
We can use this 'suvat' equation of linear motion.

${v}^{2} = {u}^{2} + 2as$
Plugging in the above values gives,

${0}^{2} = {36}^{2} + 2a(23)$


$0 = 1296+ 46a$
$46a = - 1296$
$a = - 28.2 {ms}^{ - 2}$


We can use the equation
$v = u + at$
to find the time the motorcycle took to stop.

$0 = 36 + - 28.2t$
$- 36 = - 28.2t$
$t = 1.3s$