<p>I can't figure out two questions on an old AP Physics test essay section.</p>
<p>First of all, here are the diagram and question:</p>
<p>"Blocks 1 and 2 of masses m1 and m2, respectively, are connected by a light string, as shown above. These blocks are further connected to a block of mass M by another light string that passes over a pulley of negligible mass and friction. Blocks 1 and 2 move with a constant velocity v down the inclined plane, which makes an angle θ with the horizontal. The kinetic frictional force on block 1 is f and that on block 2 is 2*f*."</p>
<p>The two questions I'm stuck on are:</p>
<p>(1) Determine the value of the suspended mass M that allows blocks 1 and 2 to move with constant velocity down the plane.
(2) The string between blocks 1 and 2 is now cut. Determine the acceleration of block 1 while it is on the inclined plane.</p>
<p>Using an acceleration of 0 is getting me nowehre. Please help. :)</p>