# Stuntman(Projectile motion)

1. Feb 12, 2013

### Toranc3

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

A movie stuntwoman drops from a helicopter that is 30.0 m above the ground and moving with a constant velocity whose components are 10.0 m/s upward and 15.0 m/s horizontal and toward the south. You can ignore air resistance.

where on the ground (relative to the position of the helicopter when she drops) should the stuntwoman have place the foam mats that break her fall?

2. Relevant equations

y=yo+vo*t+1/2*a*t^(2)
3. The attempt at a solution

I am confused on how the vectors should be drawn. It says that the helicopter has a constant velocity whose components are 10m/s up, 15m/s horizontal and toward the south. I am lost with the south part. What does it mean?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

Last edited: Feb 12, 2013
2. Feb 12, 2013

### ehild

The horizontal component of velocity points towards South.

What is the question of the problem?

ehild

3. Feb 12, 2013

### Toranc3

So the horizontal velocity toward south component is at some angle with its own components?

4. Feb 12, 2013

### ehild

????? The horizontal velocity points towards South.
You choose a system of coordinates with x axis pointing to the South and y axis pointing up. See picture. The x component of the velocity is 15 m/s and the y component is 10 m/s.

ehild

#### Attached Files:

• ###### helicopter.JPG
File size:
6.3 KB
Views:
281
5. Feb 12, 2013

### Toranc3

oh i see and thanks!

6. Feb 12, 2013

### Toranc3

I had a question about this problem again. When the stuntwoman drops from the helicopter does she have the same velocity as the helcopter? Wouldn't her y component be the oppositse sign now and still have the same x component?

7. Feb 12, 2013

### ehild

At the moment she leaves the helicopter she has the same velocity: Both the x and y components are the same as those of the helicopter.. But the y component will change with time, due to gravity.

ehild

8. Feb 12, 2013

### Toranc3

once again thanks!

9. Feb 12, 2013

### voko

This depends on how exactly she "drops". If she drops "inertially", without forcing herself out in any way, then he initial velocity will be equal to that of the helicopter. Otherwise, she will have some velocity relative to the helicopter, and her initial velocity will be the vector sum of the helicopter's and her relative velocity.

10. Feb 12, 2013

### Toranc3

Yo could you give some examples?