Question

A 0.070 kg ball attached to a 0.18 m rod of very small inertia moves in a vertical circle in such a way that it's speed remains constant. Let T₁,T₂,T₃ and T₄ be the tensions in the rod at positions1,2,3, and 4 . What rotationalspeed is required at position 3 to keep T₃ barely greater than zero?

Answer 1

Liner speed:

$v = \sqrt{Rg}= \sqrt{0.18 \times 9.81}=1.328 \;m/s$

Rotational speed:

$w = \frac{v}{R}= \frac{1.328}{0.18}=7.382 \;rad/s$