Question

A car accelerates from rest at constant rate 2m/s2 for some time. Then it retards atconstant rate 4m/s2 and comes to rest If the total time of motion be 3s , then totaldistance travelled by car is

Answer 1

Answer: 12 meteres

Explanation:

Let v, t1, t2 be the maximum velocity attained, time for which car accelerated and the time for which car retarded respectively

⇒t1 = (v−u)/a=(v−0)/2=v/2

⇒t2 = (v−u)/a=(0−v)/(−4)=v/4

Assuming the car didnt achieve uniform motion, it is given that,

⇒t1+t2=3

⇒v/2+v/4=3

⇒v=4m/s

For 3 secs, distance travelled will be 4*3 meter.

Thus the car travels 12 meters