# Homework Help: Two Masses on Same String - Conical Pendulum

1. Sep 10, 2011

### JJB11

3.(a) A particle P, of mass 0.03kg, is attached to one end of a light inextensible string OP, of length 1 m. The other end of the string is attached to a fixed point O. The particle moves in a horizontal circle, with centre vertically below O, at an angular speed of 2 revolutions per second. The string is inclined at a constant angle x to the vertical. Find both the tension in the string and the angle x.

I have done this using the conical pendulum method - x=86.4 degrees and T=4.75N

(b) A particle Q, of mass 0.02kg, is attached to one end of a second light inextensible string. The other end of this string is attached to P. The system rotates, with OP and PQ in a vertical plane that rotates about the vertical through O with constant angular speed. P moves in a horizontal circle of radius 0.75m and Q moves in a horizontal circle of radius 1.5m. The centres of both circles are vertically below O and the strings OP and PQ remain at constant angles to the vertical. Find the tension in each string.