Question

1) Brakes applied to a car produce an acceleration of 5m/s2 in the opposite direction to the motion. If car takes 1.5s to stop after applying brakes,calculate the distance travelled by it.

Answer 1

The acceleration is negative means it is retardation


Thus
a(acceleration) =-5m/s2
T(time)=1.5s


So v(final velocity)= u(initial velocity) +at
0=u-7.5
u. = 7.5m/s

now s=ut+1/2at^2

s =(7.5)(1.5) -1/2(5)(1.5*1.5)

solving this will give

s = 5.625 m approx.


hope it will help you .$