Answer:
Work = 165670.4 J = 165.67 KJ
Explanation:
First, we will find the deceleration of the car, using the 3rd equation of motion:
[tex]2as = v_{f}^2 - v_{i}^2\\[/tex]
where,
a = deceleration = ?
s = skid distance = 40 m
vf = final speed = 0 m/s
vi = initial speed = 17.2 m/s
Therefore,
[tex]2a(40\ m) = (0\ m/s)^2 - (17.2\ m/s)^2\\a = - 3.698\ m/s^2[/tex]
the negative sign indicates deceleration here.
Now, we will calculate the braking force applied by the brakes on the car:
[tex]F = ma\\F = (1120\ kg)(-3.698\ m/s^2)\\F = - 4141.76\ N[/tex]
the negative sign indicates braking force.
Now, we will calculate the work done using the magnitude of this force:
[tex]Work = |F|s\\Work = (4141.76\ N)(40\ m)\\[/tex]
Work = 165670.4 J = 165.67 KJ
