Question

a car moving at 10ms - was uniformly accelerated for 5s until it velocity reaches 20ms -. it then maintain the speed for another 20s after which the brakes were applied as the vehicle was finally brought to rest in a further 10s.draw the velocity time graph of the motion

Answer 1

v at 10 m/s at t = 0

a = (final velocity-initial velocity)/time
= (20 - 10)/5 = 2 m/s^2

so from (0,10) slope up = 2 m/s^2
to (5,20)

from (5,20) to (25,20) horizontal

from (25,20) to (35, 0 ) straight slope down (slope = -2)

Answer 2

The acceleration, (final velocity-initial velocity)divided by time =10-30 divided by 5=-4