Question

Find the initial velocity of a car which stops in 10seconds after applying brakes at the rate of 2m/s²

Answer 1

Answer:

Initial velocityGiven: Final velocity=0Time=10 secAcceleration= -2.5 m/s^2 (Negative sign as it is retardation)Using:a=v-u/t-2.5=0-u/10-2.5=-u/10-2.5*10=-u-25=-u25=u Therefore, Initial velocity is 25 m/s.

Answer 2

Answer:

Negative acceleration is retardation so,

a=-2m/s^2

the car applies brakes so the final velocity(v) is =0m/s

t=10s

a=v-u/t

-2=0-u/10

-20=0-u

u=0+20

u=20m/s

initial velocity is 20m/s