A gun of mass 3.5kg fires a bullet of 25g. the gun recoils at a speed of 8m/s-1, Calculate the velocity of the bullet.

total momentum before explosion=0

therefore total momentum after exposion=o

the book shows: m1 v1 + m2 v2,,,,,,, mass1 x velocity1 + mass2 x velocity2 ?

3.5x(-8)+0.025 v2 =0

-28+0.025 v2 =0

0.025 v2=37

v2=37/0.025 =1480m/s-1

where does the 37 come from?

should have done better at school,,,,,,thanks p,