# Homework Help: Motion in a plane question

1. Oct 6, 2009

### Lockinvar

1. The problem statement, all variables and given/known data
A hunter aims his gun directly at a monkey hanging from a high tree branch some distance away. At the instant the gun is shot the monkey drops from the branch, hoping to avoid the bullet. Show analytically, using variables, that the monkey made the wrong move.

2. Relevant equations
Linear motion equations

3. The attempt at a solution
My attempt wasent much, i have no clue where to start with it. I wrote out a list of variables of what i got out of the equation

GUN
vertical Horizontal
V1 = 0m/s V1 = 0
V2 = V2 =
a = -9.8m/s^2 a =
t = T t = T
d = Dgv d = Dgh

Monkey
V1 = 0
V2 =
a = -9.8m/s^2
t = T
d = Dm

So i figured that time was the same for all the lists, but this is absically how faar i got, i have Dm = 4.9T^2 and thats about it. I dont know where to go from here. Any help is greatly appreciated.

2. Oct 6, 2009

### willem2

what are the x and y positions of the bullet and the monkey as a function of t.

the bullet starts at B_x(0) = 0 and B_y(0) = 0
the monkey starts at M_x(0) = d and M_y(1) = h. d is distance of tree, h = height of branch

If you don't know something, such as the initial speed of the bullet, just introduce a variable and later show that is true for all values of that variable.

3. Oct 6, 2009

### tiny-tim

Welcome to PF!

Hi Lockinvar ! Welcome to PF!

How long does the bullet takes to reach the tree?

And how high up are the bullet and the monkey at that time?

Show us what you get.