Question

A motor car of mass M travels with a uniform speed v on a curved track of radius r.A spring balance loaded with a block of mass m kg is suspended from the roof of the car. The reading of the spring balance is.

Answer 1

The car is moving with an uniform velocity. And the curved bridge resembles with the arc of a circular path.

By Newton's 3rd law of motion, The force exerted on the car is central force is equal to the force exerted by the car on the bridge.

The force is equal to the product of mass of the car and square of the velocity divded by the radius of he circular path.

Hence, the reading of the spring is, $F=\frac{m{v}^2}{R}$