Concepts Of Physics MCQ Edition [Volume 1]PhysicsCircular Motion
A car travels along a horizontal circular road of radius R , with its speed increasing at a constant rate dv dt = a . The friction coefficient between the tyre and the road is . Determine the speed at which the car will skid.
Options
- A[ ( ^2 g^2 + a^2 )R^2 ]^ 1/4
- B[( g - a)R ]^ 1/2
- C[ ( ^2 g^2 - a^2 )R^2 ]^ 1/4
- D[ ( ^2 g^2 - a^2 )R^2 ]^ 1/2
Correct answer
C. [ ( ^2 g^2 - a^2 )R^2 ]^ 1/4
Step-by-step solution
The car experiences two types of acceleration while moving on the circular path: Tangential acceleration, a_t = dv dt = a Radial (centripetal) acceleration, a_r = v^2 R The net acceleration of the car is given by: a_ net = a_t^2 + a_r^2 = a^2 + ( v^2 R )^2 The net force required to keep the car moving without skidding is provided by static friction. The car will just begin to skid when this required force equals the maximum static friction force: m a_ net = N Since the road is horizontal, the normal reaction is N =