# Tension in a conical pendulum's string

1. ### mbrmbrg

494
The problem:
Figure 6-43 shows a "conical pendulum", in which the bob (the small object at the lower end of the cord) moves in a horizontal circle at constant speed. (The cord sweeps out a cone as the bob rotates.) The bob has a mass of 0.050 kg, the string has length L = 0.90 m and negligible mass, and the bob follows a circular path of circumference 0.94 m.
(a) What is the tension in the string?
(b) What is the period of the motion?

I found:
angle that string makes with vertical=arcsin(r/l)
T_y=mg
T_x=F_centripetal=ma=mv^2/r

I would like very much to find v, but I don't see how using omega will be at all helpful. period=(2)(pi)(r)/v doesn't seem to get me anywhere, either.

2. ### mbrmbrg

494
Whoa, never mind! I searched the forum and found "Conical Pendulum Problem -Right Way of Solving?" and solved the problem correctly. Joy and Jubilation!