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**1. Homework Statement**

I am trying to calculate the exit velocity of an arrow from a bow. I am an archer and this is for my own personal knowledge so I need to keep the units meaningful in lbs, sec, mph, inches. The end velocity must me in mph.

**2. Homework Equations**

The equation that I have found that best applies is:

v = (eFx/m)^-2

v = The exit velocity.

e = The efficiency (all force applied in the same direction). We can assume it will be 70% for most medieval bows.

F= The force to draw the bow fully, commonly known as draw-weight.

m= Mass of the arrow.

x= This is the distance that the string will travel from its rest position to its fully drawn position.

**3. The Attempt at a Solution**

e= 70 %

f = 100 lbs

m= .5 lbs

x = 30 inches

v= (.7x100 lbx30 inch /.5 inch) ^-2

3000 inch lbs / .5 inch

.7 x6000 lbs

4200 lbs ^-2

5.66 lbs sq

I don't understand what 5.66 lbs sq means.

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