Question

A driver of a vehicle running at the speed of 45 km per hour is a child 25 meters ahead and suddenly applies the brakes. If the retardation of the vehicle is 2 meter per second square is the child spared?

Answer 1

Answer:

Given,

Speed=20m/s,d=50m,retardation=5m/s

2

Let the ppossible reaction time be t

s

So the car moves 20tm And applied breaks with retardation 5m/s

2

So, the total distance under retardation is ≤50m

Thus the distance under the application of retardation =

2×5

20

2

−0

2

=s

′

⇒s

′

=40m

Therefore, 20t

s

+40≤=50⇒20t

s

≤50−40⇒20t

s

=10⇒t

s

≤

2

1

≤0.5s

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Answer 2

Answer:

right answer is given

Explanation:

2 . I