Question

Two identical bullets are fired one by a light rifle and the other by a heavy rifle with the same force. which riffle will hurt more ?

Answer 1

Friend the light rifle will hurt more the shoulders because see
As light rifle is light so the recoiling of the rifle will be more than heavy rifle which will hurt more.
:):):):):):) Hope it helps:):):):):):)

Answer 2

I have 3 solutions of your problem :p

1)

$\tt \small{ according \: to \: conversation \: of \: momentum,}$

$\tt P _f = P _i$

$\tt where \: P _f = total \: momentum \: after \:$

$\tt \small bullets \: fired, P _i = total \: momentum \: before \: bullets \: fired,$

$\tt here, \: P=mv =$

$\tt \small where \: m \: is \: mass \: and \: v \: is \: velocity, \\ \tt \small so \: light \: rifle \: will \: recoil \: with \: \\ \tt \small larger \: velocity \: and \: hence, \: will \\ \tt \small hurt \: the \: shoulder \: more.$

2) As both the bullets are identical and are fired with the same force. So, to reduce recall velocity, we use, heavy rifle so that its heavy mass compensate the large momentum. But for light rifle, recoil velocity will be large due to small mass thus light rifle will hurt more to the shoulder.

3) The recoil velocity of a gun is inversely proportional to its mass. Hence, the light gun will recoil more than the heavier gun. Thus, it will hurt more.