- #1

LIZard137

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## Homework Statement

A cannon of mass 1500 kg fires a 10 kg shell with a velocity of 200 m/s at an angle of 45 degrees above the horizontal. Find the recoil velocity of the cannon across the level ground.

## Homework Equations

Conservation of Momentum equation:

0=m1v1f + m2v2f

v1f = - (m2/m1)(v2f)

## The Attempt at a Solution

Ok so I'm having trouble with this problem. I could've sworn I was doing it correctly, but here it goes. Because the cannon and the cannon ball are both at rest, initial velocities don't play a part in this question (I think?). So plugging in the numbers into the equation I got:

M1 = 1500

M2 = 10

V2f = 200

V1f = - (10/1500)(200) = -1.33 m/s

The anwser to this question is 0.94 m/s, and I can't figure out what I'm doing wrong for the life of me. Any push in the right direction would be awesome!