DAY 41

***If you needed to add more to your notebook check from last week, I can check that on Tuesday. And you never know when your next notebook check will be, so.......take excellent and detailed notes!***

GOALS: SWBAT...

1. state how changes in net force and mass affect acceleration

WARM-UP

Defining Newton's First Law (2min)

• Complete the following, and think about the water in the plate:

• An object at rest stays at ____ and an object in motion stays in _____ with the same speed and in the same direction unless acted upon by a net _________ force. <--- Click the blue link to check your answer

CLASSWORK

1. 041A: Applying Newton's 1st Law of Inertia (30min)

Today you'll explore the relationship between mass and acceleration

Handout: is on Schoology as Assignment #41A, and is DUE AT THE END OF THE PERIOD TODAY

Interactive LINK: https://www.physicsclassroom.com/Physics-Interactives/Newtons-Laws/Force/Force-Interactive

2. Free Body Diagrams  - What are they?

    - Video Edpuzzle LINK (answer questions in your notes)

    - Sample Notes LINK (take notes)

Learning at Home (HW) (3 min)

1. Free Body Diagrams  - What are they?

    - Video Edpuzzle LINK

    - Sample Notes LINK

#Goals: SWBAT...

1. Describe the relationship between inertia and mass

2. Match force names to their abbreviations and to their definitions

3. Define force and the unit of force

Warm-Up (5min) 

Copy and fill in (or choose) the correct answers for the following:

• 1. Inertia: the resistance an object has to ______________

• 2.  The more inertia that an object has, the more _____ it has. 

• 3. A more massive object has a (greater/lesser) tendency to resist changes in its state of motion.

• 4. What is the meaning of "net" in relation to forces?

• 5. A net external force equal to zero means the forces are (balanced/unbalanced)

• 6. The presence of a net external force means that the object will be (accelerating/at rest)

CLASSWORK

1. #041A: What is a force?

• Force: Sometimes defined as a push or a pull on an object. Better Definition: A force is the ability to cause a change in state of motion of an object. 

•  Unit: Force is a quantity that is measured using the standard metric unit known as the Newton. A Newton is abbreviated by an "N." To say "10.0 N" means 10.0 Newton of force. One Newton is the amount of force required to give a 1-kg mass an acceleration of 1 m/s/s. Thus, the following unit equivalency can be stated:

  • 1 Newton = 1 kg • m/s2

• Is force a vector? 

2. #041B: Force Types and their Classifications

What are the classifications of force?

Take 2 minutes to review Mr. P´s notes, go here ---> LINK

Make a four column chart (see example on board) 

Using your knowledge, and the notes above, match the symbols/names of the forces with their definitions, then define each for as a ¨contact force¨ or "non-contact/action-at-a-distance/field¨ force

Definitions:

1. The force exerted by a compressed or stretched spring upon any object that is attached to it.

2. A force that is applied to an object by a person or another object.

3. The force exerted by a surface as an object moves across it or makes an effort to move across it.

4. A special type of frictional force that acts upon objects as they travel through the vacuum you can breathe. This force is often observed to oppose the motion of an object. 

5. The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself.(aka weight)

6. the force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends

7. The support force exerted upon an object that is in contact with another stable object

Symbols/Names: 

Applied Force Fa 

Gravitational Force Fg 

Normal Force FN 

Force of Friction Ff 

Air Resistance Fair 

Tension Force Ftension 

Spring Force Fspring   

Stuck? 

Help is here ---> LINK 

3. #041C: Force Scenarios

Which forces are being applied here? What are the two objects exerting/feeling the force?

• A. A dog pulls on a leash.

• B. A hammer hits a nail.

• C. You fall out of a tree toward the Earth 

• D. A car slides to a stop. 

4. #041D: Are Mass and Weight the Same?

• What do you think?

• Mass is how much ______ is in an object. In science, we call that stuff _____

• Weight is the _____ of _______ upon that stuff. 

• Which is a force, weight or mass?

5. #041E: Practice Questions

    LINK Answer 1 & 2 (complete outside of class if necessary - I'm here at lunch/nutrition for help)

Learning at Home (HW)

#041F: Lab Conclusion & other lab info

Complete Ball in a Cup Lab, due Wednesday @ 11:59pm, submitted electronically via the pre-lab document (which you already shared with me)

This should include the following. 

TITLE

NAMES & GROUP MEMBERS NAMES

PURPOSE

MATERIALS

PROCEDURE

    this should be a list of instructions specific/detailed enough that another person could read them, and do the lab correctly. 

DATA

    time data from finding Vx

    free-fall time data from finding Δt

    how you found Δx for the cup

    ***note that you can take a photo of your neat math work showing the above 

    SAMPLE CALCULATIONS should be included in the DATA section, or immediately following the DATA section

        show how you did all the math leading up to, and including, solving Δx=vixΔt

RESULTS

    what happened? (where did the ball land? Using your video, you can take a screenshot of the ball landing in the cup (or missing) and upload it to your document). 

ANALYSIS

    - Any errors? You'll need to be specific when discussing errors. For example:

        - state where in an equation you made a mistake, and how that mistake affected your results

        - describe a physical error (mistiming the displacement zone for vx, releasing the ball from too high/too low, tilted table, wrong angle for ramp, etc), and state how it/they affected your results. 

        - If you didn't have any errors, why not? What steps did you take that made your lab work so well?

CONCLUSION    

- Sum up the lab, the experience, how did it go?

If you'd like to use the template and see the rubric, here they are again

Grading Rubric  LINK

Lab Template: LINK

#Goals: SWBAT...

1. Understand the relationship between work and power

2. Solve basic work & power problems

Warm-Up (4min): Power

1. Is work a scalar or vector? What about time? What about Power?

2. Suppose that Ben Pumpiniron elevates his 80-kg body up the 2.0-meter stairwell in 1.8 seconds. If this were the case, then we could calculate Ben's power rating.

3. It can be assumed that Ben must apply an 784-Newton downward force upon the stairs to elevate his body. By so doing, the stairs would push upward on Ben's body with just enough force to lift his body up the stairs. It can also be assumed that the angle between the force of the stairs on Ben and Ben's displacement is 0 degrees. 

4. Find Ben's Power Rating

CLASSWORK

1. #041A: Power Notes

Power

• Definition: Power = the rate at which work is done

• Equation: P=W/t or Work divided by the change in time

• Unit: Watt

• 1 Horsepower = 746 Watts

• Try this: Suppose that a 40-horsepower engine could accelerate the car from 0 mi/hr to 60 mi/hr in 16 seconds. If this were the case, then a car with four times the horsepower (a 160-horsepower engine) could accelerate the same car from 0 mi/hr to 60 mi/hr in ___ seconds.

  • Another Formula for Power

    • The expression for power is work/time. And since the expression for work is force*displacement, the expression for power can be rewritten as (force*displacement)/time.

2. #041B: Practice Problems

• Let's try some problems

  • • Check Your Understanding

• • Use your understanding of work and power to answer the following questions. When finished, click the button to view the answers.