# Dynamics help

1. Jun 16, 2009

### jbenis

I don't know how to begin solving this problem so any suggestions on how to go about solving it would be greatly appreciated.

1. The problem statement, all variables and given/known data

The rope connecting slider A and mass B passes over two small pulleys, one of which is attached to A. Mass B has a constant velocity v_0, directed downwards. At the instant when y_A = b, determine: (a) velocity of A, and (b) acceleration of A. The picture of the problem can be found here: http://img8.imageshack.us/img8/2536/68824667.jpg [Broken]

2. Relevant equations

The equations that I think I need to use include the ones from rectilinear motion such as v = ds/dt, a = dv/dt.

3. The attempt at a solution

The only thing that I know is that this is a first degree problem because there are two moving objects (A and B) and the rope is the constraint.

Last edited by a moderator: May 4, 2017
2. Jun 17, 2009

### nvn

L = rope total length, yb = vo*t. Hint: ya = [0.25(L - vo*t)^2 - b^2]^0.5.

Now see if you can figure out how to compute va. After you obtain the equation for va, try the following hint. Hint: Arbitrarily let L = 2(2^0.5)*b, and let t = 0.

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