Blackwood Ballistic Pendulum Essay example

1803 Words Mar 12th, 2014 8 Pages
Experiment 6:
Blackwood Ballistic Pendulum
September 18, 2013
Jamal Wright
Zachary Floyd
Christopher Wilson

Experiment 6
Blackwood Ballistic Pendulum
Jamal Wright, Zachary Floyd, Christopher Wilson

Abstract Our goal of this experiment is to determine muzzle velocity by two methods: 1) employing uniform linear motion relations, the kinematic equations; 2) using the principles of conservation of energy and momentum. In this paper, we aim to validate the law of conservation of momentum. We do so by comparing results from two experiments conducted with a single ballistic launcher/pendulum apparatus.
Hypothesis: The initial velocity of a ballistic pendulum can be determined using the law of conservation of momentum. Momentum
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Now insert V in the momentum equation and solve for vmuzzle:
Mvmuzzle = (m + M)sqrt(2g(change in ele.)) => vmuzzle = [(m+M)/m]*sqrt(2g(change in ele.))
It should be noted that this is a perfectly inelastic collision (coefficient of restitution equals zero) and that momentum is conserved even though kinetic energy is not conserved.
Apparatus: Blackwood ballistic pendulum, pan balance and set of slotted masses, tape, plumb bob, carbon paper, 2 meter stick, meter stick and ruler.
Procedures: Weigh the ball and record its mass. The mass of the pendulum has been written on some pieces of apparatus on the flat side of the pendulum bob. Part 1: Uniform Linear Motion
1. Raise the pendulum up until the pawl catches on one of the teeth of the curved rack. Position the apparatus so that the ball will land on the floor in some convenient place. Mark the position of the frame of the apparatus so that it can be noted if there is any recoil movement. Place a piece of paper with carbon on the floor in the anticipated landing spot.
2. Cock the gun by placing the ball on the launcher until the trigger catches. This may be done easily by using the palm of one hand on the ball to push with. The palm of the other hand is placed on the gun in the usual fashion taking care not to touch the trigger.
3. Fire the ball and note its landing points. Move the paper if necessary so that the hall lands on the paper. Use several

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