Help with a conservation of momentum problem

[tommyboy2]

A 15 g bullet is fired is fired with a velocity of 220 m/s from a 6.5 kg rifle. What is the recoil velocity of the rifle?

That is the problem

I think i use the formula...

This half of the equation equals zero due to the initial velocity equaling zero = Mass of the gun*Velocity of the gun + Mass of the bullet*Velocity of the bullet

I ended up getting -.22 m/s

i converted the 15 g to kilograms I was not sure if it should have been grams or kilograms for this problem

Any help I would be greatful.

 

[Doc Al]

This half of the equation equals zero due to the initial velocity equaling zero = Mass of the gun*Velocity of the gun + Mass of the bullet*Velocity of the bullet

That's good.

I ended up getting -.22 m/s

Show how you got that answer.

i converted the 15 g to kilograms I was not sure if it should have been grams or kilograms for this problem

Standard units for mass would be kilograms.

 

[tommyboy2]

Alright thanks I thought that was the correct formula, what i was not sure about was the units thanks.