Two identical billiard balls undergo an oblique elastic collision. Initially, one of the balls is stationary. If the initially stationary ball after collision moves in a direction which makes an angle of with direction of initial motion of the moving ball, then the angle through which initially moving ball will be deflected is |
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a) |
b) |
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d) |

Two identical billiard balls undergo an oblique elastic collision. Initially, one of the balls is stationary. If the initially stationary ball after collision moves in a direction which makes an angle of with direction of initial motion of the moving ball, then the angle through which initially moving ball will be deflected is |
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a) |
b) |
c) |
d) |

1 Answer

127 votes

**(c)**

When two identical balls undergo elastic oblique collisions with one of them stationary, then after collision they will move at right angles to each other

**Alternative method I: **Just like in previous question, you can proceed using centre of mass frame of reference

**Alternative method II: **Using basic equations of conservation of momentum, conservation of energy and coefficient of restitution, you can have the desired result

127 votes

127