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Question:

harris123
harris123
Student
Community / Jr. College

What total constant force is exerted on the bullet while it is traveling down the 0.75m long barrel of the rifle?

Answer in units of N.

A 4.4 g bullet leaves the muzzle of a rifle with a speed of 322 m/s.

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Posted by harris123 on Thursday October 22, 2009 at 10:55 AM and tagged with forces, math.

Answers:

  1. kjcdb8er
    kjcdb8er Teacher

    eNotes Editor

    F = ma

    v = a * t

    x = 1/2 a*t^2

    (note these equations are only valid for a starting velocity of 0)

     

    We don't know the time the bullet is in the barrel, but we know that t = v/a.

    now x = 1/2 a*(v/a)^2 = 1/2 v^2/a or,

    a = 1/2 v^2/x = 1/2 (322 m/s)^2/0.75 m =  69 km/s^2

    Now, F = ma = 4.4 g * 69 km/s^2 = 304 g km/s^2

    Note that g km/s^2 = kg m/s^2 = 1 Newton, so

    F = 304 N

    Rate answer:

    Posted by kjcdb8er on Thursday October 22, 2009 at 11:15 AM