(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A bullet with a mass of 15 grams is fired from a rifle with a barrel that is 85 cm long.

a. assuming that the force exerted by the expanding gas to be a constant 7200N, what speed would the bullet reach?

2. Relevant equations

Ek= 1/2mv^2

Work= Force x distance

3. The attempt at a solution

Originally I thought that 7200 N were equal to Energy Kinetic so I solved like that

7200N=.5(.015)v^2...

but that seems to be incorrect.

So I found the equation for work

So I tried doing

work= 7200N x .85 meters work = 6120 J

Then setting that equal to Ek so...

6120J= 1/2(.015)v^2

v= 903 m/s

But that also seems to be incorrect.

Am I missing a step? Or am I using the wrong equation?

Please Help me, thank you in advance.

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# Homework Help: How to find velocity of a bullet given energy?

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