Force F for Balanced Masses M2, M3 on Block M1

[Kolahal Bhattacharya]

A rectangular block of mass M1 rests on the frictionless horizontal plane.On it there is a rectanglar shaped hole, drilled from upper surface.A mass M2 is on the frictionless upper surface of the block being connected through string over a pulley another mass M3 which hangs in the hole.The mass M1 is given a horizontal force F.For what value of F, M2 and M3 does not move at all?

 

[berkeman]

Woof. Is there a diagram or something included with this question?

 

[HallsofIvy]

A rectangular block of mass M1 rests on the frictionless horizontal plane.On it there is a rectanglar shaped hole, drilled from upper surface.A mass M2 is on the frictionless upper surface of the block being connected through string over a pulley another mass M3 which hangs in the hole.The mass M1 is given a horizontal force F.For what value of F, M2 and M3 does not move at all?

"On it there is a rectangular shaped hole" On what? M1 or the horizontal plane? Is the fact that the hole is rectangular relevant at all? I picture this as block M1 with block M2 sitting on top of it. Block M2 has a string attached which goes over a pully and down through the hole to M3. Is that correct?

In any case, the fact that the upper surface of M1 is frictionless means that its motion will not affect either M2 or M3 (until M1 moves out from under M2).

 

[Kolahal Bhattacharya]

You may picture the problem as following-
The M1 is like a solid block (resting on a plane) through the upper surface of which a rectangular parallelopiped portion inside the block has been removed.M2 rests on the upper surface of the block (at a distance from the drilled out hole).It is fastened to M3 (hanging inside the hole) via a string which passes over a pulley.
I do not know how to draw on this page so I cannot send you complete picture