Day 6 Conservation of Momentum Mr Lambert Integrated

+ Day 6 – Conservation of Momentum Mr. Lambert Integrated Science 1 A Trimester 1, 2014

+ Bell Ringer A 100 kg male and 80 kg male are running at the same velocity. Which male has the greater momentum? How do you know?

+ Agenda 1. Bell Ringer 2. Momentum calculations 3. Conservation of momentum demonstration 4. Conservation of momentum calculations 5. Exit Slip

+ Learning Targets On your Bell Ringer Sheet, write the following: We will apply the law of conservation of momentum to explain velocity changes during collisions.

+ Finish CER

+ Guiding Question n How can we use momentum to predict the velocity of a cart after a collision?

+ Remember: Equations n

+ Whiteboards! 2 whiteboards per group. Calculations using p = mv

+ Momentum calculations A 17. 00 kg bowling ball moving at 12. 0 m/s down the lane.

+ A 75 kg speed skater moving forward at 16 m/s

+ A 135 kg ostrich running north at 16. 2 m/s

+ An 80 kg man is running at 5 m/s. A 60 kg man is running at 7 m/s. Which man has a greater momentum?

+ If the momentum of one cart is 10 Ns before collision, while the other cart’s momentum is -5 Ns before collision, what is the total momentum of the carts after collision?

+ If the momentum of two carts is 10 Ns each before collision, what is the total momentum after collision?

+ Conservation of momentum demonstration In your notebook, copy the following table: Mass of cart 1 (kg) Mass of cart 2 (kg) 1 1 Velocity of Velocity Cart 1 before of Cart 2 collision (m/s) before collision (m/s) 0. 95 0 2 1 0. 94 1 2 0. 95 Mass of combined carts after collision (kg) Velocity of combined carts after collision (m/s) 2 0. 49 0 3 0. 69 0 3 0. 31

+ Copy this table as well: Remember: Momentum = Mass x Velocity Before the collision Momentum of Cart 1 Momentum of Cart 2 After the Collision 0. 95 0 Momentum of Combined Cart 1 & Cart 2 0. 98 0. 95 0 0. 93

+ Fill in the tables as I do the demonstration!

+ Remember…. Conservation of Momentum states: Momentum after collision = Momentum before collision

+ Video Break: Bullet into a Block n As you watch: n Why does the block move so much even though the bullet doesn’t have much mass? n http: //youtu. be/N 8 Hr. MZB 6_d. U? t=22 s

+ Videos! Newton’s Cradle • http: //www. youtube. com/watch? v=m. FNe_p FZrs. A Momentum of rockets ISS conservation of momentum • Conservation of momentum in sports • • http: //www. youtube. com/watch? v=i. Gx 3 BNV Fz 8 Q http: //www. youtube. com/watch? v=4 IYDb 6 K 5 UF 8 http: //www. youtube. com/watch? v=_w 1 i. Ev. Wsr. PI

+ Post-Demonstration questions 1. Add up the momentum of Cart 1 and the momentum Cart 2 before the collision. Compare this value to the combined momentum of the two carts after the collision. What did you find out? 2. Based on your answer to #1, was momentum conserved?

+ Conservation of Momentum simulation http: //phet. colorado. edu/sims/collisionlab/collision-lab_en. html

+ Answer the questions in your notebook: Mass = 0. 5 kg Velocity = 10 m/s Cart 1 Mass = 0. 5 kg Velocity = 0 m/s Cart 2 1. What is the momentum of cart 1 before the collision? What about cart 2? 2. What is the momentum of cart 1 after the collision? What about cart 2?

+ Mass = 1 kg Velocity = 10 m/s Cart 1 Mass = 0. 5 kg Velocity = 0 m/s Cart 2 3. What is the momentum of Cart 1 before the collision? What about Cart 2? 4. After the collision, Cart 1 travels forwards at 2 m/s and Cart 2 travels forwards at 16 m/s. What is the momentum of Cart 1 after the collision? What about Cart 2? 5. Compare the TOTAL momentum before and after the collision. Is momentum conserved?

+ Before the collision Mass = 1 kg Velocity = 10 m/s Mass = 2 kg Velocity = 0 m/s Cart 1 Cart 2 Remember… Total Momentum = 10 Velocity has a direction!! After the collision Mass = 1 kg Velocity = - 2 m/s Mass = 2 kg Velocity = 6 m/s Cart 1 Cart 2 Total Momentum = 10

+ Challenge question A large ball with mass of 2 kg is traveling at 3 m/s west. It collides with a stationary ball that has a mass of 1 kg. Upon collision, the smaller ball moves to the west at 4 m/s. What is the velocity of the larger ball?

+ How did we do…. ? We will apply the law of conservation of momentum to explain velocity changes during collisions.

+ 5 th period Correct midterms over the weekend!

+ Exit slip One cart hits and sticks to a second cart. Both carts have the same mass. Make a diagram showing the carts before and after the collision. How does the speed of the carts after the collision compare with the initial speed of the moving cart? Have a nice weekend!!