Question

A 5-kg object moves around a circular track of a radius of 18 cm with a constant

speed of 6 m/s. Find

(a) The magnitude and direction of the acceleration of the object.

(b) The net force acting upon the object causing this acceleration.

Answer 1

(a) The acceleration is centripetal, its magnitude is

$$a_c=\dfrac {v^2}{R}=200\text{ m/s}^2.$$

The centripetal acceleration is always directed toward the axis of rotation.

(b) The net force (the centripetal force) is

$$F_c=ma_c=1000\text{ N}.$$