Physics 1131 Lab 3 Due 9/18 Name ________________

Physics 1131 Lab 3 Due: 9/18 Name ________________ After this lab you should understand: 1. Newton's Third Law. 2. Conservation of momentum.

Perform the following tasks: access the PTK60 software, navigate through the appropriate menus, and analyze the video of two masses interacting on an air track. Measure and interpret position, velocity, momentum, acceleration, and force data for both masses, using graphs and the computer's measurement tools. Assess how velocities change during the collision, compare impulses, and verify conservation of momentum. Use the velocity versus time and momentum versus time graphs to determine accelerations, forces, and impulses, and check for the conservation of total momentum throughout the interaction.

Paper For Above instruction

Newton's Third Law states that for every action, there is an equal and opposite reaction. This fundamental principle underpins the interactions observed in the collision experiment involving two masses on an air track. The experimental setup uses PTK60 software to analyze the interaction, where students observe the positions, velocities, and momenta of the two masses before and after collision to confirm the law's validity and the conservation of momentum.

Initially, students play the video and select the appropriate options to analyze motion in the x-direction, plotting position, velocity, momentum, acceleration, and force graphs. Data collection involves measuring the initial and final velocities, denoted v1i, v1f, v2i, and v2f, for mass 1 (red, 0.22 kg) and mass 2 (black, 0.12 kg). The change in velocity (Δv) and momentum (Δp) for each mass are computed using the software's tools, either manually or through automated slope calculations. These measurements reveal how the velocities of the two objects change during the collision, which is crucial for understanding the force interactions.

Analyzing the velocity versus time graphs allows students to determine the accelerations (a1, a2) and corresponding forces (F1, F2) exerted on each mass during the interaction. Since force is related to acceleration by Newton's second law (F = ma), the comparison of accelerations also offers insight into which object experiences a greater acceleration. Typically, the smaller mass exhibits a larger acceleration magnitude due to its lesser inertia, although forces are equal in magnitude and opposite in direction in accordance with Newton's Third Law.

Further, students examine the momentum versus time graphs. These should show changes consistent with the impulses delivered during the collision. Calculating the area under force versus time graphs provides the impulse delivered to each mass, which should match the change in momentum, confirming the impulse-momentum theorem. An essential part of the analysis involves verifying the conservation of total momentum by summing the momenta of both masses before and after the impact, ensuring that any discrepancies are within measurement uncertainties.

Additional calculations include deriving velocities, displacements, and accelerations from the graphs. Linear fits to velocity versus time data yield the acceleration as the slope, which is then used to produce equations of motion for each mass (vy = vyo + ayt) and displacement (Dy = vyot + 0.5 ay t²). Checking these equations against graphical data validates the consistency and accuracy of measurements. The area under the velocity versus time graphs correlates with displacement, linking the graphical and algebraic analyses.

Overall, this experiment demonstrates Newton's Third Law and the conservation of momentum through graphical analysis and data interpretation. Confirming that the total momentum remains constant before and after collision, and that forces are equal and opposite during interaction, supports the fundamental principles of Newtonian mechanics. This hands-on approach reinforces the concepts through quantitative data and reinforces the understanding of force, impulse, and momentum in physical systems.

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