physics
posted by Lokesh .
A car is moving at 80km/h is subjected to a uniform retardation and brought to rest in 70seconds.find retardation and distance travelled by the car before it comes to rest.

vf=vi+a*t
but a= force/mass
vf=vi+force*time/mass
So, you need the mass of the car to determine force of retardation. 
Vo = 80,000m/3600s = 22.22 m/s.
V= Vo + a*t = 0.
22.22 + a*70 = 0,
a = 0.317 m/s^2.
V^2 = Vo^2 + 2a*d = 0.
(22.22)^2  0.63779 4d = 0,
d = 779 m. 
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