A uniform bar of length `12 L` and mass `48 m` is supported horizontally on two smooth tables as shown in the figure. A small moth (an insect) of mass `8m` is sitting on end `A` of the rod and a spider (an insect) of mass `16 m` is sitting on the other end `B`. Both the insects start moving towards each other along the rod with moth moving at speed `2v` and the spider at half of this speed. They meet at a point `P` on the rod and the spider eats the moth. After this the spider moves with a velocity `v//2` relative to the rod towards the end `A`. The spider takes negligible time in eating the insect. Also, let `v = L//T`, where `T` is a constant having value `4 sec`.

The point `P` is at

Options

A. the centre of the rod
B. the edge of the table supporting the end `B`
C. close to the edge of the table supporting the end `A`
D. none of the above

Answer

B

Explanation

Displacement of moth `= (12L)/(3) xx 2 = 8L`
`therefore` Point `P` is at the table supporting `B`.