A kitten is inside each of two boxes, initially held at rest, as shown in the diagram. Kitty together with its box weighs and Petty together with its box weighs .
When the boxes are released, which kitten will move down?
Notes
Assume that the pulleys and strings are both massless and frictionless.
The brown line at the bottom of the diagram shows that the other end of Kitty's rope is attached to the ground.
When the boxes are released, they are simply let go. No ropes are cut!