Question

A car accelerates from rest at a constant rate of
2 m/s2 for some time. Then, it retards at a
constant rate of 4 m/s2 and comes to rest. If it
remains in motion for 3 seconds, then the maximum
speed attained by the car is :


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Answer 1

Answer:

4m/s

Explanation:

v=U+at

1st- U=0,a=2 and let time taken is t

then

v=2t

when a=-4,and time becomes 3-t

your initial velocity becomes 2t

apply 1st law of motion

also given that it come to rest then your final speed come as 0

now 0=2t+(-4)*(3-t)

12=6t

t=2

v=2t,so v=2*2=4m/s

this is your ans