Calculating the Average Net Force of a 22g Bullet Fired from a Rifle

[ny_aish]

A 22 g bullet is fired from a rifle. It takes 2.55 10^-3 s for the bullet to travel the length of the barrel, and it exits the barrel with a speed of 730 m/s. Assuming that the acceleration of the bullet is constant, find the average net force exerted on the bullet

m=22g
is a=0 ? since its constant
v = 730 m/s
t=2.55 * 10^-3
I thought this is F=ma.

But its wrong! I believe I am doing this wrong, any suggestions?

 

[rock.freak667]

You can use the kinematic equations to find the acceleration. The initial velocity is zero. Hence you have the following, initial velocity, final velocity and the time, and you need to get the acceleration.

Can you find one equation that incorporates all of these terms?

 

[ny_aish]

hmmmmmm...let me give it a shot

 

[ny_aish]

my method was right but I needed to convert Grams to Kg, Thanks though!

 

[rock.freak667]

my method was right but I needed to convert Grams to Kg, Thanks though!

Yes but acceleration was not zero, had it been zero, then the resultant force would be zero as well.

 

[ny_aish]

yesssss! that's right tooo, for Acceleration i used Delta V/Delta T. Thanks :)