Shown plane mirror is lying in y-z plane. A particle P has velocity `vecu = 5hati + 6 hatj` at t=0 & acceleration `veca =2thatj`. Velocity of its image at t=2s relative to it is

Options

A. (a)`10hati`
B. (b)`-10hati`
C. (c)`20hatj`
D. (d)`-20hatj`

Answer

B

Explanation

`v_(I) = 2v_(M) - v_(0)`
= ` 2 xx 0 - (5 hati + (6+ 2t)hatj)`
`v_(I)= -5hati + 10 hatj , v_(10) = v_(I) - v_(0)`
hence `v_(Io) = -5hati + 10 hatj - (5 hati + 10hatj)`
[ at t= 2 sec] = `-10hati`