Swinging Tarzan: Solving for Maximum Height & Angle

[physicshelppls]

Homework Statement

Tarzan runs at 6 m/s and grabs a vertical vine (negligible mass) of length 4.1 m which is tied to a branch at the top. Tarzan then swings up.

Determine the maximum height Tarzan will swing up and the maximum angle the vine will make with respect to vertical.

Homework Equations

mgh = 1/2mv² ?

The Attempt at a Solution

I did a problem about the height of the swing previously, but mass was given. I would solve for m if height was given, but neither are so I'm not sure where to begin. I'm sure there is another equation. Is this a pendulum problem? We haven't covered much on pendulums. Sorry if this is not enough for an attempt at a solution.

 

[gneill]

Hi physicshelppls,

Welcome to Physics Forums!

Notice that in your relevant equation that the mass cancels on each side? You can proceed to analyze the problem leaving 'm' in as a variable, but your relevant equation implies that it will cancel out along the way.

In fact, it is common in physics to use what are called "specific quantities", where energies for example are specified in terms of Joules per kilogram (J/kg). So your conservation of energy formula becomes gh = 1/2v².

 

[physicshelppls]

Oh wow, I feel dumb for not even noticing that. So does the length of the vine not matter in finding the height?

9.8h = 1/2(6)² and I just solve for h to get the answer to the first part?

 

[gneill]

Oh wow, I feel dumb for not even noticing that. So does the length of the vine not matter in finding the height?

Nope, doesn't matter.

9.8h = 1/2(6)² and I just solve for h to get the answer to the first part?

Looks good.