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### Finding the Velocity of a Missile

```
Date: 12/10/1999 at 09:24:24
From: sally daubenspeck
Subject: Physics

If the angle of launch is 45 degrees and the distance to the target is
1000 m, what is the velocity of the missile?
```

```
Date: 12/10/1999 at 16:58:42
From: Doctor Rick
Subject: Re: Physics

Hi, Sally.

Since the angle of launch is 45 degrees, the initial horizontal
velocity is equal to the initial vertical velocity. Call this quantity
v_0.

Write an equation for the horizontal position x as a function of time
t. Set x = 1000 m and solve for t. (You'll get an expression involving
the unknown v_0.)

Write an equation for the vertical position y as a function of time t.
Plug in the value of t at which the missile hits the target. What is
the value of y at that time? (You have to make an assumption; the
problem as you stated it doesn't tell us.) Plug this value into the
equation as well.

Solve for v_0.

There are other ways you could solve this problem. You could, for
instance, solve for t first, then put it in the first equation and
solve for v_0.

If there is anything I have said that you don't understand, feel free

- Doctor Rick, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
High School Physics/Chemistry

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