Rough Draft of Physics Explanation for MythBusters Episode

We begin by outlining the ideas of mass and velocity, and from this, derive momentum.  We then outline that the books stop the bullets entirely, so the impulse is equal to the momentum.  The impulse is also Force times a change in time.  Unfortunately, we don’t know the change in time, so we can’t use this equation to derive force, which we can compare to other measurements, as it is a measure of weight (mass times acceleration, in the case of pounds, this acceleration is that of gravity).  Therefore, we present Kinetic Energy, measured in Joules (a joule is the amount of work done to move a 1 kilogram object 1 meter at a velocity of 1 m/s).  In the Final Draft, we plan on including the equation for deriving kinetic energy: 1/2*mass*velocity^2.  I then explain that this value in Joules of kinetic energy is equivalent to the value in Joules of work, which is force times distance.  We know the distance (depth into the books which the bullets went), so we can divide the distance by that and get the force.  I hope in our final video to cut directly to a video of the experiment from here, allowing for an immediate explanation using numbers and comparing the forces to values in daily life.


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