What Is the Resultant Speed After Two Birds Collide?

[drewdiddy]

Homework Statement

2 birds of same mass swoop down on a mouse at an angle of 60 deg from horizontal with speed 30 m/s. They collide and stick together, what is their resultant speed?

Homework Equations

Conservation of momentum.

The Attempt at a Solution

This was just on a test I took and I got 26 m/s but I'm thinking it should be just 30 m/s down? Or is some velocity lost during the collision?

 

[tiny-tim]

Or is some velocity lost during the collision?

Hi drewdiddy!

Momentum is always conserved in collisions (energy isn't).

So your answer was right.

 

[drewdiddy]

So it should have been 30 m/s instead of the 26 that I wrote? :(

 

[tiny-tim]

So it should have been 30 m/s instead of the 26 that I wrote? :(

No, your answer was right …

momentum is a vector, so you added the two momentums by vector addition, and you got 26 (times 2m).