DAY 46
Goals: SWBAT...
1. Distinguish between static and kinetic friction
2. Solve friction problems
3. Find the coefficient of friction between objects in the classroom.
WARM-UP:
Open CH5. --> LINK
Complete pg 141 #66, pg 142 #68 & 79 & 84 (a-c)
CLASSWORK: (for each CW activity, think about which goal you are meeting. Also, which activity helps you achieve that goal?)
1. HW Review: --> Struggle Zone
2. Hands On Activity: Finding Ff Static and Kinetic (30min)
A. You will be using the friction force and normal force to calculate the coefficient of static friction for multiple tubs of varying masses. A larger coefficient indicates a stronger friction force (AKA, a larger resistance to movement), and a smaller coefficient indicates a weaker friction force (AKA, a smaller resistance to movement)
B. Which goal from above connects to this activity?
C. Collect the materials
D. Draw a picture of the table, spring scale, and plastic tub. Show any forces present when static friction is present.
Instructions:
1. Record the tub number and mass of your tub in kg
2. Calibrate your spring scale to 0g.
3. Set up your system. Attach the spring scale to the hole on your tub. Move the tub to the end of the table.
4. Using the spring scale, apply a gentle pulling force to the tub. Record the maximum force you can apply WITHOUT the tub moving.
5. Repeat number 4 above, except this time get the tub to move at the slowest possible CONSTANT VELOCITY. Record the force
applied during the constant velocity phase.
6. Repeat steps 1-5 for a total of three tubs
7. Once you have data for three tubs, find the normal force of each tub, then find the coefficient of kinetic friction for each tub. Use the example on pg 128 if you get stuck.
***102g on the spring scale is equivalent to 1N of force***
How to use the spring scale: LINK
Homework: (it's about an hour - so I suggest you space it out...)
1. Your group must make a Google doc with all the data collected for your three tubs
FYI: 102g on the spring scale is equivalent to 1N of force
These should be in a chart (Google Sheets is good for this)
Share it with me at j.alexander@tch.birminghamcharter.com before class on Thursday 1/26
2. Read pg 131-135. Reading quiz on Thursday
3. Watch "Static and Kinetic Friction" and take notes
Watch "Static Friction on an Incline" and take notes/solve the problem with B.B.B. & Mr. P
**Take a look at the notes here. Very helpful --> LINK
There will be a couple quiz question from the videos as well, so pay attention.
4. Kahoot questions creation from pg 131-135. Make 2 Q's and A's per person. You can do this individually, or as a group (a group of 4 would need 8 Q's and A's)
On your Google doc...
Don't forget to highlight the correct answer
Share it with me at j.alexander@tch.birminghamcharter.com by 10pm Wed 1/25
Goals: SWBAT...
1. ID components and uses of common equations
2. Analyze situations in which the coordinate system is moving.
3. Solve relative-velocity problems.
WARM-UP & HW Check
Copy the four equations listed next to the projector. For each equation, complete the following. the first equation has been done by me as an example.
A. Identify each component in the equation.
B. Write the possible uses of the equation.
CLASSWORK: (for each CW activity, think about which goal you are meeting. Also, tell me how the activity helps you achieve that goal)
1. 6.1 Quiz Return
Need help? Check the solution for a similar problem here: https://sites.google.com/site/mralexandersscienceweb/physics/daily-work-1/day-44
If you still have questions, let me know. Tutoring today after school until 4:30
2. Reading Quiz 6.3
3. HW Review
4. Practice: (Use Example Problem #3 (pg 158) as an example)
Solve pg 159 26, 28, 31, #29 & 30 are Extra Credit
Answers & Hints:
26: hint: is max speed when the boat & current are moving in opposite directions?
28: 1.9x102 km/h @ 64* South of East
29. 2.8x102 km/h @ 72* North of East
30: 320km/h North
31: hmmmm....
5. CH 6 Exam Practice
A. Review the study guide from pg 163
B. Practice Problems (pg 164-167):
36, a. No, going around a curve causes a change in direction of velocity, thus the accel cannot be zero.
b. No, the magnitude of the accel may be constant, but the direction of the accel changes.
38, The force is along the string toward the center of the circle that the yo-yo makes. The string exerts the force
50, The relative speed of the two cars going in the same direction is less than the relative speed of the two cars going in the opposite direction. The passing with less relative speed will take longer.
55, 33m high 7.3m distance
57, 31m/s at 45*
58, a. 14.3s b. 497m
60, 11.8 m/s at 51*
61, a: 9.59m/s2 b. 5900 N
62, 71m/s2 Fc = 500N
68, a. 250.0km/h b. 150.0km/h
69, t(odina) = 750s; t(LaToya) = 1000s
71, 16m/s 67* from the horizon towards the west
Tutoring available after school until 4:30 Wednesday
Exam Review Session Thursday at lunch. Be there or be
HOMEWORK:
Final Exam back Friday - Corrections will be due Thursday
CH6 Test Friday 1/29
HW: Bring: 1pg sheet notes; Equation Sheet. Pencil for Scantron Problems.