Physics-
General
Easy
Question
In the given figure four identical spheres of equal mass are suspended by wires of equal length
, so that all spheres are almost touching to each other. If the sphere 1 is released from the horizontal position and all collisions are elastic, the velocity of sphere 4 just after collision is
The correct answer is: 
When the sphere 1 is released from horizontal position, then from energy conservation, potential energy at height
kinetic energy at bottom
Or 
Or 
Since, all collisions are elastic, so velocity of sphere 1 is transferred to sphere 2, then from 2 to 3 and finally from 3 to 4. Hence, just after collision, the sphere 4 attains a velocity equal to 
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