A proton collides head on with a helium atom at rest. Their combined velocity after the collision is 8 x 10^5 ms^-1. Calculate the initial velocity of the proton.

*** HELP PO PLEASE!!

3 answers

You seem to be describing an inelastic collision in which the helium and hydrogen atoms stick together to form a helium hydride molecule. If so, use the law of conservation of momentum.

Apparently your teacher or text book writer is unaware that there is no such thing as an HeH molecule.
then what can be the answer to this problem sir/maam?
The final "combined" velocity would be 1/5 of the initial velocity of the proton.

Ignore my previous comment about HeH. What you would be forming is the ion HeH+. Apparently they do exist.