Question

find the initial velocity of a car which is a stopped in 10 seconds by applying brakes. the retardation due to break is 2.5 M per second square

Answer 1

let final velocity be o and initial velocity be u

time = 10 sec
acceleration = -2.5m/s2


according to first formula

v = u + at

where v = 0

u = ?

a = -2.5m/s2
t = 10 sec
v = u + at
0 = u + (-2.5) * 10
0 = u - 25

u = 25 m/s

Answer 2

initial velocity=?

final velocity=0

time=10

accelaration=-2.5m/s2

a=v-u/t

-2.5=0-u/10

-2.5=-u/10

-2.5*10=-u

-25=-u

25=u