DAY 78
#GOALS: SWBAT...
1. Define momentum, its symbol, and its units.
2. Explain how the total momentum before a collision relates to the total momentum after a collision for elastic and inelastic collisions.
3. Calculate momentum for various situations.
WARM-UP 78 (5 minutes)
Write a shortened version (Paraphrase) of each statement in your notebook. Then say whether the statement is True of False. You have approximately 25 seconds to answer each one
Are the following statements about momentum true or false? If a statement is false, fix it :)
Momentum is a vector quantity.
The standard unit on momentum is the Joule.
An object with mass will have momentum.
An object which is moving at a constant speed has momentum.
An object can be traveling eastward and slowing down; its momentum is westward.
Momentum is a conserved quantity; the momentum of an object is never changed.
The momentum of an object varies directly with the speed of the object.
Two objects of different mass are moving at the same speed; the more massive object will have the greatest momentum.
A less massive object can never have more momentum than a more massive object.
Two identical objects are moving in opposite directions at the same speed. The forward moving object will have the greatest momentum.
An object with a changing speed will have a changing momentum.
CLASSWORK
078A: Momentum Practice
Paraphrase each question into your notes, then answer it
1. Which of the following objects have momentum? Include all that apply.
a. An electron is orbiting the nucleus of an atom.
b. A UPS truck is stopped in front of the school building.
c. A Yugo (a compact car) is moving with a constant speed.
d. A small flea walking with constant speed across Fido's back.
e. The high school building rests in the middle of town.
2. A truck driving along a highway road has a large quantity of momentum. If it moves at the same speed but has twice as much mass, its momentum is ________________.
3. A physics cart rolls along a low-friction track with considerable momentum. If it rolls at the same speed but has twice as much mass, its momentum is ____.
4. Two objects, A and B, have the same size and shape. Object A is twice as massive as B. The objects are simultaneously dropped from a high window on a tall building. (Neglect the effect air resistance.) The objects will reach the ground at the same time but object A will have a greater ___. Choose all that apply.
d. none of the above quantities will be greater
5. A 4 kg object has a momentum of 12 kg•m/s. The object's speed is ___ m/s.
a. speed
b. acceleration
c. momentum
6. Analyze the Relationships Between Variables. The first two have been done for you as examples:
Given: An object with a mass M and a velocity v has a momentum of 32 kg•m/s. An object with a mass of ...
... 2M and a velocity of 2v would have a momentum of 128 kg•m/s. (doubling mass and doubling velocity means multiply old answer by 4)
... 2M and a velocity of 0.5v would have a momentum of 32 kg•m/s. (doubling mass and halving velocity means multiply old answer by 1)
... 0.5M and a velocity of 2v would have a momentum of ____ kg•m/s.
... 0.5M and a velocity of 0.5v would have a momentum of ____ kg•m/s.
... 4M and a velocity of v would have a momentum of ____ kg•m/s.
... 4M and a velocity of 0.5v would have a momentum of ____ kg•m/s.
... 0.5M and a velocity of 4v would have a momentum of ____ kg•m/s.
... 3M and a velocity of 2v would have a momentum of ____ kg•m/s.
078B: Concept Builder: Momentum
Correctly answer 12 questions about momentum to earn all three trophies.
Paraphrase each question into your notes, then write the answer
LINK: https://www.physicsclassroom.com/Concept-Builders/Momentum-and-Collisions/Momentum/Concept-Builder
076A: Momentum Knowledge Inventory
- enter your answers on Schoology
LEARNING AT HOME (HW)
078C: Watch the video, take notes, and answer edpuzzle questions
Lecture Notes: https://www.flippingphysics.com/uploads/2/1/1/0/21103672/0180_lecture_notes_-_introduction_to_conservation_of_momentum.pdf
EdPuzzle: https://edpuzzle.com/media/588648f58c8de93e3be6f1be
2018-2019
#GOALS: SWBAT...
1. Define momentum, its symbol, and its units.
2. Explain how the total momentum before a collision relates to the total momentum after a collision for elastic and inelastic collisions.
3. Calculate momentum for various situations.
WARM-UP
Find the momentum of the following two carts
Cart A: 0.5-kg physics cart loaded with one 0.5-kg brick and moving with a speed of 2.0 m/s.
Cart B 0.5kg physics cart loaded with three 0.5-kg bricks moving with a speed of 2.0 m/s
CLASSWORK
078A: Yesterday's CW/HW Review: Momentum Guided Reading
078B: Egg Drop Interactive
Activity Instructions & Questions: https://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/Egg-Drop/Egg-Drop-Exercise
Interactive Simulator: https://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/Egg-Drop/Egg-Drop-Interactive
LEARNING AT HOME (HW)
1. Complete 078B
2. I'll use the Remind App to keep you posted regarding the strike. There will be a final court decision today, and hopefully it will be announced before school lets out. In the meantime, I'm assuming we have school tomorrow, and you should too.
Goal:
SWBAT
1. describe patterns of constructive and destructive interference
2. properly create a setup to measure the width of human hair
WARM-UP
1. How wide is one piece of your hair? cm? mm? 0.1mm? more? less?
2. Another way of asking this question - how many hairs stacked side-by-side would be equivalent to the width of this line? ---> |
3. What is constructive interference?
4. What is destructive interference?
5. Copy the image from the board - how many wave patterns would be created by the object blocking the light source?
6. Does a laser light beam expand as it travels, or does it stay the same diameter?
CLASSWORK
078A: Review Refraction from Day 77 (VIDEO)
078B: "How wide is your hair?" Lab
LINK Read (skip #11). Also note that to save time, steps 1-4 will be different, as we will be mounting the hair directly to the front of the laser.
Copy the data table from pg 7 into your notebook
Materials: Ruler, strand of hair, tape, piece of paper, laser
Discuss safety:
List three safety concerns:
To collect data, you'll need the laser on for an extended period of time. Should you tape the power button on? Why/Why not?
Lasers are fragile. Describe how you can handle them to keep them functioning.
Practice time:
For successful data collection, you'll need to...
...mount the hair to the front of the laser. Today we will practice that.
...move your table or chair so that the distance between the hair and the target (paper on the wall) is less than or equal to one meter. Today we will practice that as well.
If you can get both of the above correct, I'll initial your data chart, and you'll be ready to begin the data collection portion of the lab tomorrow at the beginning of class.
Data Analysis.
You'll be measuring the initial (close) and final (far) sides of each fringe. Why not just measure the middle of the fringe?
How do we find the average distance of each fringe from the central point?
Tomorrow we will collect data, and analyze the data you collect
HOMEWORK
Review the lab, as we will do it tomorrow.
Make up any late homework from the past week.
This Friday we will have an exam on Waves. You should update your Table of Friends (equation sheet), and begin reviewing.