PHY Lab - Collisions (1)

Steven Garcia – Marquez Linear Momentum in Collisions Goal: To investigate the Law of Conservation of Linear Momentum in collisions. Simulation Used: Collision Lab from the PhET at the University of Colorado . Preliminary Settings.  Open the simulation Collision Lab .  From the menu on the right, select: Show Values  In the yellow window below, click on "More Data" Activity 1: Elastic Collisions in one dimension. Ball 2 is initially at rest.  On the menu to the right, slide the indicator all the way to the right for a perfectly elastic collision.  For the given masses and initial speeds of the two balls, determine the velocity and momentum after the collision.   Ball     Mass (kg)   Before the Collision After the Collision       V (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       0.50     1.20     0.60     0     0   2       0.50     0     0     1.20 0.60 Momentum initial = 0.60 Momentum final = 0.60   Ball     Mass (kg)   Before the Collision   After the Collision       v (m/s)     Momentum (kg.m/s)     v (m/s)   Momentum (kg.m/s)   1       1.50     0.90     1.35     0.45     0.68   2      0.50      0     0     1.35     0.68 Momentum initial = 1.35 Momentum final = 1.35   Ball     Mass (kg)   Before the Collision After the Collision       v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       0.50     1.40     0.70     -0.70     -0.35   2       1.50     0     0     0.70     1.05 Momentum initial = 0.70 Momentum final = 0.70 Question:  Is the momentum conserved?  Yes  

Steven Garcia – Marquez Question:  Is the kinetic energy conserved? Yes Activity 2: Elastic Collisions in one dimension. Balls 1 and 2 initially moving in the same direction.   Ball     Mass (kg)   Before the Collision After the Collision       v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       0.50     0.80     0.40     0.30     0.15   2       0.50     0.30     0.15     0.80     0.40 Momentum initial = 0.55 Momentum final = 0.55   Ball     Mass (kg)   Before the Collision   After the Collision         v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       1.50     1.20     1.80     0.85     1.27   2       0.50    0.50      0.25     1.55     0.77 Momentum initial = 2.05 Momentum final = 2.04   Ball     Mass (kg)   Before the Collision   After the Collision         v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       0.50     1.20     0.60     -0.15     -0.08   2       1.50     0.30     0.45     0.75     1.13 Momentum initial = 1.05 Momentum final = 1.05 Question:  Is the momentum conserved? Yes Question:  Is the kinetic energy conserved? Yes

Steven Garcia – Marquez Activity 4: Inelastic Collisions. On the menu to the left, slide the indicator all the way to the left to ensure perfectly inelastic collision.   Ball     Mass (kg)   Before the Collision   After the Collision         v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       0.50     1.20     0.60     0.60     0.30   2       0.50     0     0     0.60     0.30 Momentum initial = 0.60 Momentum final = 0.60   Ball     Mass (kg)   Before the Collision   After the Collision         v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       1.50     1.20     1.80     0.85     1.27   2       0.50     -0.20     -0.10     0.85     0.42 Momentum initial = 1.70 Momentum final = 1.69   Ball     Mass (kg)   Before the Collision   After the Collision         v (m/s)     Momentum (kg.m/s)     v (m/s)     Momentum (kg.m/s)     1       0.50     1.20     0.60     -1.05     -0.53   2       1.50    -1.80     -2.70     -1.05     -1.58 Momentum initial = -2.10 Momentum final = -2.11 Question:  Is the momentum conserved? Yes Question:  Is the kinetic energy conserved? No Acknowledgements. Tatiana Stantcheva, Northern Virginia community College. The Java Applet comes from the PhET Interactive Simulations at the University of Colorado, Boulder. Some activities are based on the "Laboratory Manual, Physics 231 - 232" by Walter Wimbush, Northern Virginia Community College, 2008.