Question

A car starts from rest is uniformly accelerated at 0.1m/s square untill it reaches a speed of 15m/sec square. It travels at this speed for 3mins and it returns uniformly retarded so as it come to rest 8mins after starting.plot the velocity time graph of the motion and use the graph to determine

Answer 1

speed is m/s

v = at
it accelerated for 15/.1 = 150 seconds

after another 150 seconds, until t=150 s = 5 min. Then it decelerated for the remaining 3 minutes, or 180 seconds. That means it decelerated at 15/180 = 1/12 m/s^2

v(t) =
t/10 for 0 <= t <= 150
15 for 150 < t < 300
15 - (t-300)/12 for 300 <= t <= 480