Copy of Lab - Momentum.docx

Physics Lab Momentum This experiment will have you set up a colliding pendulum apparatus, conduct collisions of varying strength, take measurements in order to calculate the momentum of the objects, and to compare the momentum of the system before and after the collision. Procedure: 1. Read through the Momentum Lab on pages 73-76 in the CPO Physics lab manual. Note that you are NOT going to do the same lab as what is printed in the book. However, you are going to set up the same apparatus and take the same type of measurements. 2. Answer the pre-lab questions in your lab report. 3. Measure the masses of the projectile ball and the target ball, with the target ball being the larger of the two. Record the masses in kilograms in the data table. 4. Measure the diameters of the projectile ball and the target ball. Record these in meters in the data table. 5. Set up the colliding pendulum apparatus as described in the lab manual. Set the starting block to its maximum setting at the 60 mark. 6. Pull up the projectile ball to the starting block and release. Measure the photogate times and record. 7. Repeat the experiment two more times. 8. Move the starting block to the 50 mark. Repeat steps 6 and 7. 9. Continue to move the starting block to lower settings and repeat the experiment. At some point, the projectile ball will not be fast enough to have a measurable collision with the target ball. At that point, do not collect any more data. Pre-lab Questions: 1. What measurement(s) must be made or calculated in order to determine the momentum of one of the masses in this experiment? mass of the objects and their velocities 2. How are each of these measurements made or calculated using the tools involved in this particular experimental setup? Mass is measured by an electronic balance scale and diameter is measured by a caliper. Time is measured by the photogates Data Section: Mass (kg) Diameter (m) Projectile Ball 0.0673 kg .0252 m Target Ball 0.131 kg .0314 m (sample collision data table) Stop Mark at 60 Trial Projectile Time Before Collision (t 0 , in seconds) Projectile Time After Collision (t p , in seconds) Target Ball Time After Collision (t t , in seconds) 1 0.0117s 0.0436 s 0.0296s 2 0.0116s 0.0402s 0.0232s 3 0.0117s 0.0494s 0.0244s Average 0.0117s Project time before collisions from trial (1 + 2 + 3)/3 0.0444s (trial 1 + 2 + 3)/3 0.0257s (trial 1 + 2 + 3)/3

Stop Mark at 50 Trial Projectile Time Before Collision (t 0 , in seconds) Projectile Time After Collision (t p , in seconds) Target Ball Time After Collision (t t , in seconds) 1 0.0137s 0.0494s 0.0295s 2 .0139s .0484s .0273s 3 .0141s .0556s .0290s Average .0139s .0511s .0286s Stop Mark at 40 Trial Projectile Time Before Collision (t 0 , in seconds) Projectile Time After Collision (t p , in seconds) Target Ball Time After Collision (t t , in seconds) 1 .0171s .0576s .0326s 2 .0171s .0641s .0329s 3 .0174s .0698s .0401s Average .0172s .0638s .0352s Stop Mark at 30 Trial Projectile Time Before Collision (t 0 , in seconds) Projectile Time After Collision (t p , in seconds) Target Ball Time After Collision (t t , in seconds) 1 .0229s .1056s .0472s 2 .0226s .1038s .0601s 3 .0227s 0.0872s 0.0418s Average .0227s .0989s .0497s (repeat the above table for the other stop mark settings) Analysis Section: Calculate the following for each stop setting. Show ONE sample calculation of each (equation used without numbers, equation repeated with numbers, answer rounded to the correct number of significant figures). Record your answers in a results table (see sample below). 1. The velocity of the projectile ball before the collision, and the velocity of the projectile and target balls after the collision. (Be sure to watch the signs, indicating direction!) 2. The momentum of the projectile ball before the collision, and the momentum of the projectile and target balls after the collision. (Again, watch the signs!) 3. The total momentum of the projectile ball and target ball after the collision. (Again, the signs!) 4. The difference between the momentum of the projectile ball before the collision and the total momentum of the system after the collision. (sample results table) (include as many columns as you have data recorded) Results Table: Stop Mark 60 50 40 30 20 Projectile Velocity Before Collision (v 0 ) (m/s) V=d/t 60/.0117 =5128 3597 2325 1321 Projectile Momentum Before Collision (p 0 ) (kg-m/s)