Question

a 1.75kg pistol lies at rest on an essentially frictionless bench. it accidentally fires and shoots a 25 gram bullet parallel to the bench. How far has the bullet moved by the time the gun has recoiled 2.60mm?

Answer 1

the velocityies of the bullet and the gun are proportional to the ratio of masses.

Vbullet/vgun= massgun/massbullet

now, in the same time, the distances are proportional to velocities, so

distancebullet/distancegun= massgun/massbullet

so go figure.