Question

# Three identical blocks and are placed on horizontal frictionless surface. The blocks and are at rest. But is approaching towards with a speed 10 . The coefficient of restitution for all collisions is 0.5. The speed of the block just after collision is

- 5.6
- 6
- 8
- 10

## The correct answer is: 5.6

### For collision between blocks and ,

from principle of momentum conservation,

Or

Adding Eqs. (i) and (ii), we get

Similarly for collision between and

…(iv)

Adding Eqs. (iii) and (iv) we get

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