DAY 61
Student Survey Links
Encuesta de Estudiantes - Español
Parent Survey Links
Encuesta para Padres - Español
Essential Question: How can I show that energy cannot be created or destroyed, but CAN be transported from one place to another, and CAN be transferred between systems?
#Goals: SWBAT...
1. Draw and explain a molecular model showing what happens to the skater’s molecules at the microscopic level as thermal energy increases, then relate this to what is happening at the macroscopic level of the skater on the ramp.
2. Differentiate between total energy and various forms of energy in a system.
3. Determine the type of energy present in a variety of scenarios.
Explain how each model (bar graph and pie chart) shows the total energy of the system, and draw each model for a situation with a different amounts of initial energy.
4. Describe energy changes in a system over time using both words and graphical representations
Standards
That there is a single quantity called energy is due to the fact that a system’s total energy is conserved, even as, within the system, energy is continually transferred from one object to another and between its various possible forms. ((HS-PS3-1), (HS-PS3-2)
Conservation of energy means that the total change of energy in any system is always equal to the total energy transferred into or out of the system. (HS-PS3-1)
Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems. (HS-PS3-1)
The availability of energy limits what can occur in any system. (HS-PS3-1)
Warm-Up (3min): Energy Skate Park Introduction
Click on the following link: http://phet.colorado.edu/sims/html/energy-skate-park-basics/latest/energy-skate-park-basics_en.html
Explore the simulation, and answer the questions below.
What can be done with the skater?
What tools do you have available?
What is the difference between the three screens (tabs at bottom)?
CLASSWORK
1. 061A: Questions from Day 60 KE and PE classwork
https://sites.google.com/site/mralexandersscienceweb/physics/daily-agenda-classwork/day-60
2. 061B: Conservation of Mechanical Energy HW Review
Leave 15 spaces in your notes here for the HW (KE & PE Review)
3. 061C: What's the Connection Between Friction and Thermal Energy?
Here's the handout: https://drive.google.com/file/d/0B31ORq_bI3-VT1pYUzVFSkUxekJsY25rTm1qbVo5RUZxZDQw/view?usp=sharing
When you rub your hands together, describe what is happening (in terms of energy)? Where does the energy come from? How is friction involved?
What happens to the objects/molecules in a system when energy is converted to Thermal Energy?
Friction Simulation: http://phet.colorado.edu/sims/html/friction/latest/friction_en.html
Follow the directions on page 1, and fill in the microscopic and macroscopic models.
some microscopic concepts to consider: speed of individual molecules, size of molecules, temperature of molecules
some macroscopic concepts to consider: how energy changes form, how heat is released, why the skater doesn't return to the same height on the ramp
Share out/Whole class discussion
4. This is for tomorrow, but if you're ahead today, feel free to attempt it.
062A: Energy Changes in the Skate Park System
Follow directions to complete pages 2-3
Observe the forms and quantities of energy in the system at different positions
Some key concepts to consider:
Should total energy remain constant?
How can you give the skater the highest initial energy?
The total energy represents the sum of _______________________
How is this represented on a pie chart?
How is this represented on a bar graph?
Share out/Whole class discussion
At Home Learning (HW)
061D: KE and PE Review
answer the questions on pages 12-26. Skip page 19
Since the question numbers are all over the place, use the following numbering system to record your answers.
Number each question based on the page number. Your paper should look like this:
12: answer
13: answer
14: answer
15: answer
16: answer
17: answer
18: answer
(skip 19)
20: answer
21: answer
22: answer
23: answer
24: answer
25: answer
26: answer
Link to assignment: https://drive.google.com/file/d/1lHhrljJHfpNihOlfHYSkKF2HgULZd7L_/view?usp=sharing
#Goals: SWBAT...
1. Determine if mass can be cancelled from all terms in the equation
2. Determine if a scenario represents work
3. Solve work problems
Warm-Up (4min): Did Everyone Bring Mass to the Party?
You have to be able to identify when mass cancels out of an equation.
Recall: The “equation” is the party and the individuals are the terms delineated by a subtraction, addition or equal sign.
Stuck? Confused? Check this LINK for help
Copy the equations below, then answer the question, which is: "Can mass be cancelled in the equation?" If it can, cancel it (show your work). If it can't, write why you can't cancel mass.
0 = max - Ff (assume FN=Fg)
mgh + 1/2mv2 = 4kx2
1/2mvi2 = 1/2mvf2 + mgL(1− cosθ)
Ftension - Fg = may
CLASSWORK
1. #061A: Building Your Problem Solving Skills
Recall: W = F • d • cos Θ where F is the force, d is the displacement, and the angle (theta) is defined as the angle between the force and the displacement vector.
Solve the following. Draw FBD's. Show all work. Include units and correct sigfigs.
If you get stuck, or want to check your answers, there's a link to help in the Homework section below
Instructions: For each case, indicate which force(s) are doing work upon the object. Then calculate the work done by these forces.
A) A 10-N frictional force slows a moving block to a stop after a displacement of 5.0 m to the right.
B) A 10-N force is applied to push a block across a frictional surface at constant speed for a displacement of 5.0 m to the right.
C) An approximately 2-kg object is sliding at constant speed across a friction free surface for a displacement of 5 m to the right.
D) An approximately 2-kg object is pulled upward at constant speed by a 20-N force for a vertical displacement of 5 m.
3. Before beginning its initial descent, a roller coaster car is always pulled up the first hill to a high initial height. Work is done on the car (usually by a chain) to achieve this initial height. A coaster designer is considering three different incline angles at which to drag the 2000-kg car train to the top of the 60-meter high hill. In each case, the force applied to the car will be applied parallel to the hill. Her critical question is: which angle would require the most work? Analyze the data, determine the work done in each case, and answer this critical question.
a.
b.
c.
Angle
35 deg
45 deg
55 deg
Force
11,200N
13,900N
16,100N
Distance
105 m
84.9 m
73.2 m
Work (J)
4. Ben Travlun carries a 200-N suitcase up three flights of stairs (a height of 10.0 m) and then pushes it with a horizontal force of 50.0 N at a constant speed of 0.5 m/s for a horizontal distance of 35.0 meters. How much work does Ben do on his suitcase during this entire motion?
5. A force of 50 N acts on the block at the angle shown in the diagram. The block moves a horizontal distance of 3.0 m. How much work is done by the applied force?
6. How much work is done by an applied force to lift a 15-Newton block 3.0 meters vertically at a constant speed?
7. A student with a mass of 80.0 kg runs up three flights of stairs in 12.0 sec. The student has gone a vertical distance of 8.0 m. Determine the amount of work done by the student to elevate his body to this height. Assume that his speed is constant.
8. Calculate the work done by a 2.0-N force (directed at a 30° angle to the vertical) to move a 500 gram box a horizontal distance of 400 cm across a rough floor at a constant speed of 0.5 m/s. (HINT: Be cautious with the units.)
9. A tired squirrel (mass of 1 kg) does push-ups by applying a force to elevate its center-of-mass by 5 cm. Estimate the number of push-ups that a tired squirrel must do in order to do a approximately 5.0 Joules of work.
At Home Learning (HW)
1. Complete all problems from #061A
If you got stuck, answers and more help are here at this link: LINK
2. #061B: Monday we will cover Kinetic and Potential Energy: Watch/take notes/complete edPuzzles on the following:
(5:25) Introduction to Kinetic Energy with Example Problem - EDpuzzle
(5:48) Introduction to Gravitational Potential Energy with Zero Line Examples - EDpuzzle
Unit Goals: What is a wave? How do they act? How are do waves differ?
Goals: SWBAT...
1. Predict how density affects energy transfer in a wave
2. Compare and contrast transverse and longitudinal waves
3. Analyze wave speed
Warm-Up (5min):
1. give an example of an object which has high density, and an object that has low density
2. PREDICTION: Imagine you have two ropes tied together - one low density, and one high density. If you give the low density rope a pulse with amplitude 1m, do you think the amplitude of the high density rope will be the same 1m, higher than 1m, or lower than 1m? Explain why.
CLASSWORK
1. #061A: Exploring Waves
Today you'll take another look at waves, this time from a slightly different perspective as our inquiry activity from Monday/Tuesday. Most importantly, you'll consider wave speed, and begin to look at sound waves.
Directions:
1. Use your handout as a guide. If you're absent, the link to the handout is here: LINK
2. The simulation is here: LINK
2. #061B: Oral Quiz - Waves (from wave simulation #059A)
At Home Learning (HW)
1. Complete #061A
2. Quiz Friday on waves, (wavelength, frequency, amplitude, their interactions, plus medium, plus how waves interact (the video from day 57), etc)