Question

The driver of a car travelling at speed v suddenly sees a wall at a distance r directly infront of him. To avoid collision, should he apply the brakes or turn the car sharply away from the wall ? Give reason.

Answer 1

Answer:

Hey!

Let F1 be the braking force, so as to stop the car just in the distance r.

Then,

work done by the braking force = kinetic energy of the car

or F1 x r = 1/2 mv2

or F1 = (mv2) / 2r ...1

Let F2 be th force required (centripetal force force) for taking a circular turn of raduis r.

Then,

F2 = mv2 / r ...2

From the equations (1) and (2), we have

F1 = 1/2 F2

Since the force needed to apply brakes is just half of the force required to take the circular turn, it is better to apply brakes.

Thank you ❤️