Question

A car starts from rest to cover a distances. The coefficient of friction
between the road and the tyres is u. The minimum time in which the car
can cover
the distance is proportional to​

Answer 1

Answer:

The answer is: the minimum time is proportional to 1/square root of mu.

Answer 2

Answer:

the minimum time is proportional to 1/square root of mu.

Explanation:

To change car speed, a force (horizontal in this case) must be applied to it. The force with the same magnitude will be applied to the ground because of Newton's Third law. If one would try to apply a force greater than the friction force UMG a car would slip on the ground.

By Newton's Second law, the maximum acceleration will be a = UMG/m = ug where m is the mass or a car and g is the gravity acceleration. The distance as a function of time will be:

s(t) = at²/2 = ugt²/2

So, for a fixed distance S the minimum time will be:

t = root 2s/ug

 

This is proportional to  "1/square root u

Hope it will help you