Question

Solve Question No. 9

Answer 1

u=72km/h=20m/s
v=0m/s
s=100m
v^2-u^2=2as
0-400=2(a)(100)
-2m/s^2=a
v=u+at
0=20-2t
t=10s.

Answer 2

u= 72km/hr= 72*5/18=20m/s

v=0m/s

s=100m

a=?

t=?

v^2 =u^2 +2as

0=20*20 + 2a*100

-400=200a

a= -400/200

a= -2 m/s^2

v= u+at

0= 20 +(- 2t)

-20= -2t

t = 20/2

t= 10sec