A ball A of mass M collides elastically with a similar ball B at rest as shown in figure. Initially velocity of ball A is u m/s. After collision,

Options

A. Speed of ball B is u `sin theta`
B. Velocity of ball A is `u sin^2 theta hati + u sin theta cos theta hatj`
C. Speed of ball A is `u cos theta`
D. `Velocity of ball B is `u cos theta sin theta hati + u cos^2 theta hatj`

Answer

B

Explanation

`implies barV_A = u sin theta(sin theta hati + cos theta hatj) = u sin^2 theta hati + u sin theta cos theta hatj`
`barV_(B) = u cos theta(cos theta hati - sin theta) = u cos^2 theta hati - u sin theta cos theta hatj`
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