# Homework Help: Help Cirular Motion <3

1. Nov 17, 2006

### Karex

Tarzan (m=85kg) tries to cross a river by swiming from 10.0m long vine. His speed at the bottom of the swing, just as he clears the water, is 8.0m/s. Tarzan doesnt know that the vine has a breaking strength of 1.0*10^3 N. Does he make it safely across the river?

mass= 85kg
rope= 10m
velocity= 8.0m/s
Tension= 1.0*10^3N
and it has to do with this equation somehow

Fc(force that maintains circular motion)
mass (m)
Vt^2 (tangential speed)^2
r (distance to axis)
w (angular speed)

Fc=m*((Vt^2)/r) or Fc=m*r*(w)^2

I know the answer is no :grumpy: but i dont know how to get there
well thanks again

2. Nov 17, 2006

### OlderDan

Think about all the forces acting on Tarzan at the bottoom of his swing. The net force must equal the centripetal force. Some of that total foce is the tension in the vine.

3. Nov 17, 2006

### QuantumCrash

Hmmm.... This looks familiar.
Try analysing all the forces acting on Tarzan. With quite a number of assumptions you will find there is only 2. Then find the point where the Tension is maximum.

Centripetal force is the net force of the 2 forces. This is actually almost like a pulley question.