How Is Acceleration Calculated for a Bullet in a Rifle Barrel?

[iiskenny]

The barrel of a rifle has a length of 0.877 m. A bullet leaves the muzzle of a rifle with a speed of 612 m/s.
What is the acceleration of the bullet while in the barrel? A bullet in a rifle barrel does not have constant acceleration, but constant acceleration is to be assumed for this problem.
Answer in units of m/s2.

 

[rock.freak667]

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