# Homework Help: Find Initial Velocity (With Wind Factored In)

1. Feb 16, 2010

### SomeGuy121

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

2. Relevant equations

3. The attempt at a solution
I can't do it =\.

Q: What equation would I use to find initial velocity? Given: Wind Speed, Wind Angle, Coordinates of Origin, Coordinates of End Point, (Distance), Projectile Mass, Theta (Angle to Use)

Here's my repost from a previous topic:

Hey Physics Forums. This is my first post here, and I'm just wondering about how to find what the initial velocity SHOULD be based on all the other information that I provide (it's for a program application I coded).

Anyways, I have this right now (which is for no wind/0 wind):

I am just wondering how I would go about factoring in the "wind" and wind's angle.

Wind Angles:

^ 90
< 180 > 0
\/ 270

As you can see, the wind angle starts at East 0 and increases counter-clockwise.

Anyways, here's the formula:

Velocity = Sqrt((Mass * (DifferenceInX^ 2)) / (2 * (DifferenceInX) * Sin(Theta* PI / 180) * Cos(Thtea * PI / 180) - (2 * (DifferenceInY)) * ((Cos(Theta* PI / 180) ^ 2))))

Where Theta is the angle of the shot; Difference in X is the difference in coordinates X of the starting position and where you want the shot to end; and DifferenceInY is the difference in coordinates Y of the starting and ending position.

I don't take a Physics course yet, I'm enrolled in Algebra 2 at the moment, but am heavily interested in the Physics course of study, so please do help me out!

I need an equation, like the one above, that will work in my computer program.

Last edited: Feb 16, 2010
2. Feb 16, 2010

### SomeGuy121

Also, the velocity remains constant; it doesn't change...

3. Feb 16, 2010

### SomeGuy121

I don't know why my question hasn't been answered as of yet! This isn't homework, this is off-to-the-side-what-I-do work.

I have no idea how to begin to make this all work. I've been looking for an answer for over 5 months!!!

4. Feb 16, 2010

### SomeGuy121

I'll include a picture with equations for finding initial velocity in zero wind.

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5. Feb 16, 2010

### SomeGuy121

The final line is the line to find initial velocity in 0 wind.

Velocity = Sqrt((Mass * (DifferenceInX^ 2)) / (2 * (DifferenceInX) * Sin(Theta* PI / 180) * Cos(Thtea * PI / 180) - (2 * (DifferenceInY)) * ((Cos(Theta* PI / 180) ^ 2))))