Question

Starting form a rest, a car moves with uniform acceleration and attains a velocity of 72km/hr in 20 sec.It then moves with uniform speed for 25 sec and is then brought to rest in 10 sec.Under uniform retardation.Find the total distance travelled using velocity time graph.​

Answer 1

From t= 0 to t=15

v= u + at , at t=15 , v=72kmph or 20m/s and u= 0

So , equation will be y=mx +c where c= 0 and m is acceleration a.

Plugging in values we get a = 4/3

So graph will be y=4/3x for t=0 to t=15

From t=15 to t=35 graph is y=20

From t = 35 to t= 45 , v=0 u= 20m/s

Similary from above, a= 20/10 = 2m/s^2

So graph will be y= -2x