How Do You Calculate the Velocity of a Compass Joint in Motion?

[scintillate10]

Homework Statement

An engineering student holds her open compass perpendicular to the drafting board, touching the board with both tips of the compass. She slowly closes the compass so that the tips move toward each other with a speed of 2 v_naught = 0.060 m/s. Initially the angle between the arms of the compass is 2theta=60 degrees. The arms of the compass are L = 15 cm long.

Calculate the velocity of the joint of the compass as a function of time.

AND Give the velocity of the joint at the moment that she starts to close the compass and at the moment that the two tips reach each other.

Homework Equations

I'm not sure but maybe L^2 = x^2 + y^2

or v = omega r

The Attempt at a Solution

I have no idea where to start this equation but the answer is really complex looking and involves a unit vector j . . .

 

[member 553083]

I'm thinking it's something with the velocity of the joint and the angle of the compass somehow? I would really appreciate it if someone could help me out here. Thanks!