Question

A lead fishing weight of mass 0.2 kg is tied to a fishing line that is 0.5 m long. the weight is then whirled in a vertical circle. the fishing line will break if its tension exceeds 60 n .

Answer 1

In the movement of the weight in vertical circle, using momentum balance, the largest tension is at the bottom of the circle. This is represented by:

F = T - m g
T = F + m g
F (centripetal) = mv^2/r
= m v^2 / r + m g

m v^2 / r = T - m g
T= 0.5m * 100kgm/s^2 / 0.2kg - 9.81m/s^2 * 0.5m
T= 245 m^2/s^2