Answer:
F = -8820 N
Explanation:
Given that,
The weight of a car, W = 19600 N
Initial speed of the car, u = 30 m/s
It is brought to rest, final velocity, v = 0
Distance, d = 100 m
We need to find the average friction force acting on it.
Firstly we find the acceleration of the car using third equation of motion. Let it is a.
[tex]v^2-u^2=2as\\\\a=\dfrac{v^2-u^2}{2d}\\\\a=\dfrac{(0)^2-(30)^2}{2\times 100}\\\\=-4.5\ m/s^2[/tex]
Average frictional force,
F = ma
m is mass, [tex]m=\dfrac{W}{g}=\dfrac{19600\ N}{10\ m/s^2}=1960\ kg[/tex]
F = 1960 kg × -4.5 m/s²
= -8820 N
So, the average friction force acting on it is 8820 N.
