Mirror is moving towards the particle with speed 2 cm/sec. Speed of A ad B are `10sqrt(2)` and 5 cm/sec respectively in the direction shown in figure. Magnitude of velocity of image of the particle B with respect to image of A.

Options

A. `sqrt325 cm//sec`
B. `15 cm//sec`
C. `13 cm//sec`
D. `sqrt269 cm//sec`

Answer

A

Explanation

Velocity of image of particle B,
`overset(u)V_(B) = 5i + 4 (-i) = i`
Velcoity of image of particle A,
`overset(u)V_(A) = 10 (-i) + 4(-i) - 10j`
`:. overset(ur)V_(A) = -14i - 10j`
Relative velocity of image
`overset(u)V_(BA) = overset(u)V_(B) - overset(u)V_(A)`
`= I - [14(-i) - 10j]`
`= 15i + 10j`
`:. overset(ur)V_(BA) = sqrt325 cm//sec`