Question

A car is travelling at 20 m/s along a road. A child runs out into the road 50 m aread and the car

driver steps on the break pedal. What must be the car’s deceleration be if the car is to stop just

before it reaches the child ::::Find Deceleration​

Answer 1

Answer:

$2as = {v}^{2} - {u}^{2}$

Car stops so v = 0

$2a(50) = {0}^{2} - {20}^{2} \\ \\ a = - \frac{400}{100} = - \: 4m {s}^{ - 2}$

Answer 2

Answer:

-4ms-2

Explanation:

v2-u2=2as

0-400=2*a*50

-400=100a

a=-400/100=-4