Kinematics Question 380

Question: A car accelerates from rest with a constant acceleration α on a straight road. After gaining a velocity v1 , the car moves with the same velocity for some-time. Then the car decelerated to rest with a retardation β . If the total distance covered by the car is equal to S, the total time taken for it’s motion is

Options:

A) Sv+v2(1α+1β)

B) Sv+vα+vβ

C) (vα+vβ)

D) Svv2(vα+1β)

Show Answer

Answer:

Correct Answer: A

Solution:

From v = u + at, we have v=0+αt1vα

0=vβt3t3=vβ.

Now, S =12vt1+vt2+12vt3=v22α+vt2+v22β
t2=Svv2(1α+1β).

Hence, t1+t2+t3=Sv+v2(1α+1β)



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