Question

A 3.1 kg ball is tied to a string and swung in a horizontal circle at a speed of 7.2 m/s. the radius of the circle is 2.2 m.

What angle does the string make with the horizontal?

What is the tension in the string?

Answer 1

Assume the string makes an angle theta with the horizontal and tension in the string is T.

T*Cos theta = m*v^2/r (centrifugal force)
and T*Sin theta = m*g

By dividing: Tan theta = g*r/v^2
= 9.8*2.2/7.2^2
= 0.41
So Theta = 22.5 deg
Now T=m*g/Sin22.5 = 79.3N