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26/10/2021 6:36 pm
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A car is travelling at 20 m/s along a road. A child runs out into the road 50 m ahead and the car driver steps on the brake pedal. What must the car’s deceleration be if the car is to stop just before it reaches the child?
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26/10/2021 6:38 pm
Initial velocity, u = 20 m/s
Final velocity, v = 0 m/s
Distance, s = 50 m
Using relation, v2 = u2 + 2as
02 = (20)2 + 2 x a x 50
02 = 400 + 100a
a = \(\frac{-400}{100}\) = -4 m/s
The car’s deceleration must be 4 m/s2.
This post was modified 3 years ago by Mayank1444