On a frictionless surface, a block of mass M moving at speed collides elastically with another block of same mass M which is initially at rest. After collision the first block moves at an angle to its initial direction and has a speed . The second block's speed after the collision is :
As we discussed in
Conservation of Energy and Conservation of Mechanical Energy -
Accounting all forms of energy within isolated system
i.e. total energy remains constant.
Perfectly Elastic Collision -
Law of conservation of momentum and that of Kinetic Energy hold good.
According to conversation of energy