Question

Which causes a greater effect to the magnitude of the velocity of an object in uniform circular motion: variation in centripetal force or variation in radius?

Answer 1

The centripetal force can be found as follows:

$$F_c=ma_c=m\dfrac{v^2}{r}.$$

From this formula we can find the velocity:

$$v=\sqrt{\dfrac{F_cr}{m}}.$$

As we can see from the formula, the variation in centripetal force and variation in radius causes the same effect on the velocity.