If friction can provide necessary centripetal force, why should the road be banked?

A train runs along an unbanked circular track of radius 30 m at a speed of 54 km/h. The mass of the train is 106 kg. What provides the centripetal force required for this purpose - The engine or the rails? What is the angle of banking required to prevent- wearing out of the rail?

Explain why friction is necessary to make the disc in Fig. 7.41 roll in the direction indicated. (a) Give the direction of frictional force at B, and the sense of frictional torque, before perfect rolling begins. (b) What is the force of friction after perfect rolling begins?

When a wheel is rolling on a level road, what'is the direction of frictional force between the wheel and the road?

What is the angle between frictional force and instantaneous velocity of the body moving on a rough road?

A car starts from rest on a half kilometer bridge. The co-efficient of friction between the tyres and road is 1. Show that one can't drive through the bridge in less than 10 sec.

The gravitational force between two objects of small masses on the surface of the earth can be neglected. Why?

A swimmer can swim with Velocity of 10 km/h. w.r.t, the water flowing in a river with velocity of 5 km/h. In what direction should he swim to reach the point on the other bank just opposite to his starting point?

A curve road of diameter 1,8 km is banked so that no friction is required at a speed of 30 ms^-1 . What is the banking angle.

Figure 5.18 shows a man standing stationary with respect to a horizontal conveyor belt that is accelerating with 1 m s^2 . What is the net force on the man? If the coefficient of static friction between the man’s shoes and the belt is 0.2, up to what acceleration of the belt can the man continue to be stationary relative to the belt? (Mass of the man = 65 kg.)