Question

The wheels of an automobile are locked as it slides to a stop from an initial speed of 30.0 m/s. If the coefficient of kinetic friction is 0.600 and the road is horizontal, approximately how long does it take the car to stop?

Answer 1

Answer:

  x = 76.5 m

Explanation:

Let's use Newton's second law at the point of contact between the wheel and the floor.

     fr = m a

     fr = miy N

     N-W = 0

     N = W

     μ mg = m a

     a = miu g

    a = 0.600 9.8

    a = 5.88 m / s²

Having the acceleration we can use the kinematic relationships to find the distance

     $v_{f}$² = v₀² + 2 a x

    $v_{f}$ = 0

    x = -v₀² / 2 a

Acceleration opposes the movement by which negative

   x = - 30²/2 (-5.88)

   x = 76.5 m