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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 

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 
to ask about it.

- Doctor Rick, The Math Forum   
Associated Topics:
High School Physics/Chemistry

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