Question

A car is travelling at a speed of 72 km/h. Brakes are applied so as to produce a uniform acceleration of-2.5 m/s². Find how far the car will go before it is brought to rest​

Answer 1

A train is travelling at a speed of 90 km h-1. Brakes are applied so as to produce a uniform acceleration of –0.5 ms-2.

Answer 2

Answer is 288m

Explanation:

Speed before applying brakes= 72kmph

= 20m/s [ 72*5/18]

initial velocity (u) = 20m/s

Final velocity (v)= 0[since, car comes to rest after applying

brakes]

Acceleration= v-u/t [time]

=⟩ -2.5 = 0-20/t

=⟩-2.5t = -20

=⟩2.5t = 20

=⟩ t = 200/25 [multiplying 2.5 and 20 by 10]

=⟩t = 8s —— Eq.1

Avg.velocity = (v+u)/2

= (0+72)/2

= 72/2

= 36 m/s—— Eq.2

Now,

Dist. travelled= Avg.velocity*time

=Eq.1 * Eq.2

=36*8

=288m

(Hope this helps)