What is the initial velocity of a car before it brakes

I have a car with mass 1500kg that skids for 14.5m
The coefficient of friction is 0.8

However, after skidding for 14.5m the car is still travelling at 17m/s.

what is the initial velocity and what is the acceleration (or deceleration).


Thanks!

Acceleration due to friction = -μg = 0.8*9.8 = - 7.84 m/s^2

Using v^2 = u^2 + 2as

U^2 = 17^2 –2 * ( -7.84)14.5

U = 27.27 m/s
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k ( coefficent of friction) = 0.8
g = 10 m/s2
m= 1500 kg

Force on the car while skidding = k*m*g = 0.8*1500*10

Retardation on the body = F/m = 0.8*1500*10/1500 = 8m/s2 ( accel is -8m/s2)

now by eqn of motion
v^2 - u^2 = 2as
u^2 = v^2 -2as
= 17*17 + 2*8*14.5 = 289 + 232 = 521
u = 22m/s (approx)

use energy

(1/2)mv^2-Fr*D=0

(1/2)*1500*v^2-0.8*1500*9.8*14.5=0

Solve for v.
v=15.08m/s