Question

find the initial velocity of a car which is stopped in 10 seconds by applying brakes . the retardation due to brakes is 2.5 m\s^2.



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Answer 1

retardation =-a=2.5m/s^2

t=20s

v=0

we know that

v=u+at

in case of retardation

v=u-at

u=at

u=2.5*10

u=25m/s

Answer 2

Initial velocity = ?

Final velocity = 0

Time = 10 sec

Acceleration = -2.5 m\${s}^{2}$

↓Formula used :- ↓

v = u + (a)(t)

0 = u + (-2.5) (10)

0 = u - 25

u = 25m\s