Question

a particle moves along a circle with a uniform speed v. After it has made an angle of 60degree, the change in its speed and velocity will be

Answer 1

The question says uniform speed, so there is no change in the magnitude of the velocity.
Hence there is no change in the speed of the particle.

Assuming that the particle started traversing the circle at the top most position in the clockwise direction,
Initial velocity is
v in x direction and 0 in y direction.

After an angle of 60 degree is covered, as I said the magnitude of the velocity will remain the same but its Direction will change.
Therefore the new velocity is

vcos60 in x direction and vsin60 in y direction
v/2 in x direction and v×(root3/2) in y direction

This is how one would solve, but this depends on where the particle started.
So we can only say

There is no change in the speed of the particle.
There is no change in the magnitude of the velocity of the particle.
The direction of the velocity of the particle has changed by 60 degrees in the direction (clockwise or anticlockwise) the particle is travelling in.

Answer 2

Answer:

so the change in velocity is 0 and velocity is v