# Homework Help: Impulse Question (Really Difficult)

1. Nov 15, 2007

### ll Source ll

1. The problem statement, all variables and given/known data
A bird is initially perched on a swing with a mass of 153 g. The bird has a mass of 52 g. The swing is 8 cm below the point of attachment to the top of the cage. The bird/swing are initially at rest. The bird takes off horizontally at 2 m/s. How high will the base of the swing rise above its original level? Disregard friction.

2. Relevant equations
Where do i start?

3. The attempt at a solution
ive used several formulas that dont work out i just need to know which formula to use im completely and utterly lost on this problem. Ive tried m1v1 + m2v2 = m1v1f + m1v1f , didnt work. and mgh = 1/2mv^2. Any help ? :(

Last edited: Nov 15, 2007
2. Nov 15, 2007

### Dick

What's the momentum of the bird when it leaves? The perch will have an equal and opposite momentum backwards. (This is treating the bird as more of a projectile than a flyer - but I think that's the intent of the problem).

3. Nov 16, 2007

### ll Source ll

sweet thx dood! :) (I figured it out)