question_answer

Consider elastic collision of a particle of mass m moving with a velocity u with another particle of the same mass at rest. After the collision the projectile and the struck particle move in directions making angles \[{{\theta }_{1}}\]and \[{{\theta }_{2}}\]respectively with the initial direction of motion. The sum of the angles. \[{{\theta }_{1}}+{{\theta }_{2}},\]is                    [UPSEAT 2004]

A)             \[45{}^\circ \]

B)             \[90{}^\circ \]

C)             \[135{}^\circ \]         

D)             \[180{}^\circ \]