Question

The stones tied on top are evenly rotating in a vertical plane. Upholstery
the difference between the maximum and minimum values of the pulling force of the wire
If ∆T = 10N
Find the mass of the stone m.

Answer 1

At the top:

$$T_t=m\frac{v_t^2}{r}-mg,T_b=m\frac{v_b^2}{r}+mg$$

From the conservation of energy:

$$0.5mv_t^2+2mgr=0.5mv_b^2$$

$$T_b-T_t=6mg$$

$$10=6(9.8)m$$

$$m=0.17\ kg$$