Question

A car starts from rest and accelerate uniformely at 4m/s^2 for 6 seconds. for the next 8 sec. the driver moves with constant velocity. After this the driver applies brakes and stops the car in 10 sec. What is the total distance travelled by the car?

Answer 1

V1 = a*t = 4 * 6 = 24 m/s.
d1 = 0.5a*t^2 = 0.5*4*6^2 = 72 m.

d2 = V*t = 24 * 8 = 192 m.

V = Vo + a*t = 0.
a = -Vo/t = -24/10 = -2.4 m/s^2.

V^2 = Vo^2 + 2a*d = 0.
d3 = -(Vo^2)/2a = -(24^2)/-4.8 = 120 m.

d = d1+d2+d3.