8/16 Summer Physics class

1. A Denver Bronco is running towards the end zone at 11 m/s (25mph). A Pittsburg Steeler running directly behind him at 15 m/s (34mph) tackles him and causes him to fumble directly into the hands of another Steeler who runs it back for, the final seconds, game winning touchdown!!! If the Bronco weighs 127 kg (280lbs) and the Steeler weighs 136 kg (300 lbs), what is their momentum after impact and before hitting the ground? (Use metric #'s only. Others are there for reference.) (Check answer when finished below.)

2. Two train cars are moving towards each other along a track. One has a mass of 32,000 kg and is traveling at 3.5 m/s. The other has a mass of 23,000 kg and is traveling at 5 m/s. Assuming they stick together after impact, what is their final velocity? (Check answer when finished below.)

3. Describe throwing a bowling ball down the alley and knocking down all the pins as far as energy transfer goes. Start with holding the ball and end with the last pin falling. Be sure to name all the objects that are doing work and name all objects that are having work done on them. Extra Credit: Show me the #'s and calculations.


AND
Use this website https://phet.colorado.edu/sims/collision-lab/collision-lab_en.html to complete the following questions:


Phet Momentum Homework


Click on the "Advanced Tab" at the top of the screen.


1. Click on the "Momenta Diagram" button in the upper right.


2. Click on the "Show Values" button in the upper right.


4. Click on "1 Dimension" button in the upper right.


5. Click on the "More Data" button in the lower left.


6. Set the speed of ball 2 to 0 (Drag the vector arrow for ball 2 until V = 0)


7. Notice the total momentum of both balls. (In the momenta box to the lower right)


8. Click play.


9. How does the total momentum of the system after collision, compare to the total momentum before collision?


10. Now, make both balls have a mass of 1.5. What happens to their velocity after collision?


11. How about their total momentum before and after collision how do they compare?


12. Now click "Add Ball" at the bottom. This ball should have a mass of 2 and a velocity of 0.


13. Now click play. Watch the total momentum vector on the "Momenta" graph. How does the total momentum after collision change?


14. Add a ball and do it again. Notice anything about the momentum vector now?


15. Please feel free to play with this. Add balls, try two dimensions, what ever you wish.


Answers to math problems.

1. MV of Bronco + MV of Steeler = Mass of both x velocity of both
(11m/s x 127Kg) +(15m/s x 136Kg) = 263 x Vf
1379 + 2040 =263v
13.1m/s = V

2. MV of car 1 + MV of car 2 = Mass of both x velocity of both
(32,000 x 3.5) + (23,000 x -5) = 55,000 x Vf Notice that the second speed is negative due to the opposite direction of travel. I assigned moving right as positive and moving left as negative.
112,000 + -115000 = 55,000 Vf
-3m/s = Vf (the cars will be moving to the left)