# Homework Help: Relative Motion and Two-Dimensional Motion

1. Sep 11, 2011

### shortman12012

1. The problem statement, all variables and given/known data

A blimp is ascending at the rate of 7.6 m/s at a height of 67 m above the ground when a package is thrown from its cockpit horizontally with a speed of 4.5 m/s.
(a) How long does it take for the package to reach the ground?

(b) With what velocity (magnitude and direction) does it hit the ground?
magnitude
direction ° below the horizontal

3. The attempt at a solution

I'm not really sure how to start this problem exactly. I know I'll have to use vectors and add them up but i just need some help setting up the problem please

2. Sep 12, 2011

### Hootenanny

Staff Emeritus
Well, what is the package's initial velocity?

3. Sep 12, 2011

### shortman12012

well i know the package's initial velocity is 4.5 m/s. I'm just not sure how to combine both the movement of the blimp and then calculating the velocity of the package as well

4. Sep 12, 2011

### Hootenanny

Staff Emeritus
Not quite.
The package's initial velocity is the sum of its velocity relative to the blimp and the blimp's velocity.

5. Sep 12, 2011

### shortman12012

so would it be
Velocity of package to ground = velocity of package to blimp + velocity of blimp to the ground?
V(PG) = V(PB) + V(BG)
then i just use vector addition and get the velocity for V(PG)?

6. Sep 12, 2011

### Hootenanny

Staff Emeritus
Yes