Question

A stone of mass 3 kg attached at one end of a 2m long string is whirled in horizontal circle. The string makes an angle of 45° with the vertical then the centripetal force acting on the string is ______.

(g = 10 m/s² , tan 45° = 1)

Options

• 20 N

• 30 N

• 10 N

• 40 N

Answer 1

A stone of mass 3 kg attached at one end of a 2m long string is whirled in horizontal circle. The string makes an angle of 45° with the vertical then the centripetal force acting on the string is 20 N.

Explanation:

For conical pendulum `tan theta="v^2"/"rg"`

`therefore"v"^2/r=g tantheta=10xxtan45^circ=10xx1=10  "m/s"^2`

Centripetal force `F="mv"^2/r=2xx10=20  N`