# Homework Help: Finding the initial velocity

1. Oct 6, 2009

An arrow with a mass of 90g is fired from a bow whose string exerts an average force of 125 N on the arrow over a distance of 74 cm.

so: m=90g=.090kg, F=125N, d=74cm=.74m

Then find the initial velocity of the arrow as it leaves the bow.
i cant seem to find the equation that would fit this problem any help or advice would be greatly appreciated

2. Oct 6, 2009

### rock.freak667

Conservation of energy.

What is the work done by the bow on the arrow converted to?

3. Oct 6, 2009

### Delphi51

The bow is like a spring, so if you have any spring formulas you could use them. If you could find the energy given to the arrow by the spring, you could then find the velocity. Or you could work with force and acceleration to get the velocity. Have a go and show your work so we can help!

4. Oct 6, 2009

### rl.bhat

Force is given, mass is given. Find the acceleration. Arrow starts from rest and the accelerates till it travels through 0.74m.
What is relation between displacement, acceleration, initial velocity and final velocity?