An alpha particle mass(4u) experience head on collision elastically with nucleus mass(197u) what is the percentage of its original kinetic eneegy

Answer 1

The full solution to the 1d elastic collision problem (obtained by combining conservation of momentum with the relative velocity condition (v₁-v₂) = (v₂'-v₁') ) is

v₁' = (2m₂/(m₁+m₂))v₂ + ((m₁-m₂)/(m₁+m₂))v₁

Note that when m₂ >>m₁ , if v₂ = 0 v₁' = -v₁ (reflection from a wall) and if v₁ = 0 a stationary ball hit by a wall moving at v₂ in the negative direction would bounce the ball with a velocity of 2v₂ in the negative direction.

If you want v₂' , it is the same equation with all 1 and 2 switched.

So plug in and find v₁' , then you can take the ratio of E_K'/E_K for 1. (It will be substantially higher than 1)

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