Answer:
speed of the car before the brakes were apply is 12.35 m/s
Explanation:
given data
accident measured distance = 73 feet = 22.25 m
to find out
speed of car before the brakes
solution
we consider here coefficient of kinetic friction between the road and the tires is 0.35
and we take speed of the car just before skidding = u
and final speed of car will be v = 0
now we apply here work energy theorem
so
0.5 mv² - 0.5 mu² = (- coefficient of kinetic friction × mass × g ) distance .......1
0.5( v² -u² ) = (- coefficient of kinetic friction × g ) distance
put here value and we get
0.5 ( 0 - u² ) = (- 0.35 × 9.8 ) 22.25
solve it we get
u = 12.35
speed of the car before the brakes were apply is 12.35 m/s
