Swinging on a Vine? - Calculate Tension with Physics

[fball558]

swinging on a vine??

Homework Statement

Consider the example of Tarzan swinging on a vine. Let the length be L = 10 m, and Tarzan
has a mass of M = 70 kg. The figure shows him swinging through the bottom of the arc,
where at that instant he has a speed of 13.0 m/s. What is the tension in the vine?

A. 686 N
B. 823 N
C. 1869 N
D. 1153 N
E. 1335 N

The Attempt at a Solution

is there an easier way to solve this instead of using the angular momentum principle?? if so how??

 

[mgb_phys]

Draw a diagram listing all the forces.
hint there are two forces down at the bottom of the arc)

 

[fball558]

Draw a diagram listing all the forces.
hint there are two forces down at the bottom of the arc)

i know there is the F(tension) which points up. and the F(gravity) pointing down.
F(gravity) = -mg
but how do you know the F(tension)

 

[fball558]

never mind i got it. forgot centripetal force :)
thanks