circular motion

A simple pendulum, suspended from a fixed point, consists of a light cord of length 500 mm and a bob of weight 2.0 N. The bob is made to move in a horizontal circular path. If the maximum tension which the cord can withstand is 5 N show whether or not it is possible for the radius of the path of the bob to be 300 mm.

Reply 1

phys981

I think for starters we have to assume that the radius IS 300mm then work out what value for Tension that gives.

If the radius is 300mmm then we have a 3 4 5 triangle

EDITED BECAUSE I CAN'T TELL MY SINES FROM MY COSINES

Resolving vertically, mg = t cosa where a is the angle made with the vertical. We can calculate a because we know the sides of the triangle: cosa =4/5.

so we can also calculate T - T = mg/0.8 = 2.5N so yes, it is possible.

This seems a lot simpler than I though it was going to be. Have I overlooked something?