Velocity problem

1. Oct 6, 2009

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

A bullet with a mass of 1.5g is fired from a gun with an initial force of 500 N over 20m
Find the initial velocity of the bullet as it leaves the muzzle.

2. Relevant equations

m=1.5g, F=500N, d=20m

3. The attempt at a solution

i cant seem to find the equation that would fit this problem any help or advice would be greatly appreciated

2. Oct 6, 2009

Delphi51

Given the force, you can find the acceleration easily.
Have you got an accelerated motion formula with no t in it?
There is one with just velocity, acceleration and distance that just kills this kind of question.

If you don't have it, I suggest you find the time it takes to travel the 20 m long gun barrel (wow, long one!). Then you can use the usual accelerated motion formulas to get the speed at that time.

3. Oct 6, 2009

i need to find the initial velocity, there is no acceleration involved i just cant find any equation that would work

the best one ive found is v^2= (kx^2)/m but i cant find k from the info i have so im stuck. if i had k then i could solve this problem.

4. Oct 6, 2009

Delphi51

The question is poorly worded - it wants the velocity when the bullet leaves the gun and that would better be called the final velocity.
It most certainly will accelerate with 500 N applied to .0015 kg.

v^2= (kx^2)/m looks like a spring formula. You don't have a spring here.