vERY vERY URGENT HELP NEEDED

[saleena]

HEY GUYS cOULD U HELP IN SOLVING THIS PHYSICS QUESTION
A sub atomic particle of mass 0.113u collides head on and elastically with a stationary neutron.The neutron moves off with a speed of 3800000 meters per second.Calculate for the sub atomic particle
(a)its initial speed
(b)its final speed


thanks in advance

 

[imagine]

apply the principle of momentum.... ie momentum b4 impact = mometum after impact
hope u know the formula of momentum hehe