Question

A robber riding a bike on a straight road see the police van standing 190 m ahead and applied brakes this causes the bike to slow down at the rate of 15 metre per square if it takes 5 seconds to stop explan whether it hit or not

Answer 1

Answer: Bike didn't hit the police van

Explanation: As we know that the police van is 190m ahead of the biker so we have find such a answer which lies between 0 and 190 (0 < x < 190)

so as per the question

a = - 15 m/s^2 , t = 5s and v = 0 ( as bike stops at last )

applying 1st formal equation of motion for uniform acceleration i.e v = u+at we can find u.

Evaluating the terms

0 = u + (-15)(5)

75 = u

Now using third formal equation of motion i.e v^2 - u^2 = 2as to find displacement

Evaluating the calculated data in the above equation

(0)^2 - (75)^2 = 2(-15)s

0 - 5625 = -30s

-5625/-30 = s

187.5m = s

So our calculated answer is smaller than 190

it mean that bike didn't hit the police van

Hope this helped you