Question

A car accelerates from rest with constant
acceleration of 4 m/s2, then retards at rate of
3 m/s2. If total time is 14 seconds, then
maximum speed will be :
(1) 24 m/s
(2) 20 m/s
(3) 30 m/s
(4) 15 m/s​

Answer 1

Explanation:

Let v,t

1

,t

2

be the maximum velocity attained, time for which car accelerated and the time for which car retarded respectively

⇒t

1

=(v−u)/a=(v−0)/2=v/2

⇒t

2

=(v−u)/a=(0−v)/(−4)=v/4

Now it is given that,

⇒t

1

+t

2

=3

⇒v/2+v/4=3

⇒v=4m/s

Hence correct answer is option C