Physics Lab 3 - Conservation of Linear Momentum Melissa Polewczak Kassi Xifo and Melissa Eppler PHYS 2115-009 November 1 2012 ABSTRACT When two objects

# Physics Lab 3 - Conservation of Linear Momentum Melissa...

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Conservation of Linear Momentum Melissa Polewczak , Kassi Xifo, and Melissa Eppler PHYS 2115-009 November 1, 2012 ABSTRACT When two objects are in motion and they collide, that linear momentum of the system remains unchanged, but instead is transferred equally and oppositely throughout the two objects. To measure this, objects placed on an air track were collided in elastic and inelastic collisions, and their velocities and masses were measures. The average of the first two collisions showed a ∆ P system of -0.023, and -0.027. The average of the inelastic collision showed a ∆ P system of 0.094. Overall, the momentum in all three systems was conserved with slight room for uncertainty. 1
INTRODUCTION Newton’s first law generally states that an object in motion will stay in motion, unless acted on by an outside force. Without any other force acting on the object, including friction, the objects speed and direction will remain constant. In other terms this means that the object’s velocity vector will remain the same from the initial moment that it begins to move. In most cases, an object’s mass will also remain constant throughout time. This constant mass combined with its constant velocity makes up linear momentum. Linear momentum is defined as the continued constant movement of an object over time and it can be found with the equation mv . Newton’s second law Is a major factor when more than one object is involved. The total amount of force exerted on the object is equal to the mass times the acceleration. The acceleration of an object is the change in velocity over the change in time so that would then be related to the total force. The equation F = M * Δv/Δt is then derived from the previous information. These equations though only tell what the impulse and linear momentum is, while Newton’s third law is needed to find the momentum after objects collide. When two objects collide their momentum is transferred to each other. This is known as the conservation of linear momentum. This law can be defined by this following equation: M A V Ai + M B V Bi = M A V Af + M B V Bf . The total momentum in a system will remain constant because each of the objects will have equal but opposite momentum before and after the collision. Momentum is always conserved but the only thing not conserved is the total mechanical energy in the system when the two objects stick together rather than bouncing off of each other. This can be measured by the kinetic energy equation: KE = ½mv for the initial and final 2
velocities of the objects. The difference in total kinetic energies before and after collision will then find the change in the mechanical energy. This will differ for the type of collision. The two types of collisions objects can have are elastic and inelastic. Elastic collisions occur when the objects hit into one another and either one or both of the objects move in separate directions. Two variations of this collision includes the objects moving toward each other with
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