I\'ve been stuck on this problem for a while now and I\'m not sure what to do. T

Question

I've been stuck on this problem for a while now and I'm not sure what to do. The problem is dealing with polar coordinates. Here's the problem statement:

To increase his speed, the water skier A cuts across the wake of the tow boat B, which has a velocity of 60 km/h.  At the instant when =30°, the actual path of the skier makes an angle =50° with the tow rope. For this position, find the absolute velocity of the skier.

What I have so far is this (and I could be completely off):

Basically I'm getting stuck on finding theta dot. I have two unknowns but I can't find another equation. Obviously I need to convert e sub theta into i hat and j hat but I still have the same problems.

Does any one have any helpful information? I'm kinda just stuck.

Explanation / Answer

First off the skier is in circular motion. Thus V_A/B is tangent to the curve which is the theta axis. Using that, I drew the triangle that related V_A, V_B, and V_A/B. I then used Law of Sines to determine V_A and V_A/B. Looked like this:

sin(40) / V_B = sin(120) / V_A = sin(20) / V_A/B

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