Particles of masses 2M, m and M are respectively at points A, B and C with AB=1/2(CB). M is much -much smaller than M and at time t =0, they are at rest as given in figure.
At subsequent times before any collision takes place

Options

A. m will remain at rest
B. m will move towards M
C. m will move towards 2M
D. m will hve oscillatory motion

Answer

C

Explanation

`F_("net")=(2GMm)/((AB)^(2))-(GMm)/((2AB)^(2))`
`=(2GMm)/((AB)^(2))-(GMm)/(4(AB)^(2))=(7GMm)/(4(AB)^(2))` (along BA)
Hence m will move towards BA (i.e., 2M)