Question

A stone attached to a string is whirled round in a horizontal circle at a constant speed of l5 m/s.

What is the difference in the velocity when the stone is (i) at opposite ends of a diameter (ii) in two

positions A and B, where the angle AOB is 90o

with O as the centre of the circle?​

Answer 1

Explanation:

Let the mass of the stone be m which is moving with uniform speed v in a circle of radius r.

The magnitude of velocity is constant but the velocity vector keeps changing its direction at every instant. Hence the linear momentum of the stone changes its direction continuously.

Angular momentum

L

=m(

r

×

v

)=mrv

z

^

Hence the angular momentum is constant in magnitude and always points in z axis.