HP Cycle 17

🟢 5: M 12/16 - ↩️ Pivot circular motion lab (2) & "centripetal force"

Today, we'll discuss what you found from your part of the lab ↩️ Pivot lab "Forces in Circular Motion".  We'll put together the findings from each of the three different groups (see ✏️ Google Classroom for the assignment), and we'll discuss how we might come up with one mathematical model for centripetal force.  

Then, we'll further explore uniform circular motion quantitatively by investigating a car losing control when rounding a curve in icy conditions.  We'll discover how we can apply previous knowledge of Newton's Laws in solving this problem and discuss the reasons we should SLOW DOWN when driving in adverse weather conditions.

We'll do the following sample problem:  It takes a 900-kg racing car 12.3 seconds to travel at a uniform speed around a circular racetrack of 90.0-meter radius.

• What is the centripetal acceleration of the car?

• How much centripetal force is acting on the car?

• What provides the centripetal force?

• What is the minimum coefficient of static friction required to make the turn without slipping?

Presentation:  Circular Motion Example Problems (only slides 1-6 today)

Homework:  Finish Formative #1-16  by Tuesday, December 17th at 10pm.  Quiz on Basic Uniform Circular Motion next class!  

Optional Extra Practice:  Centripetal Acceleration and Force CompuSheets.  ANSWERS.   

🟩❗ 5: W 12/18 - uniform circular motion problems

Quiz on Basic Uniform Circular Motion TODAY!

Today, we'll spend time working through some circular motion example problems:

• car rounding a curve (if we didn't finish this last time)

• rotor ride

• Vertical Circles (extra presentation)

Vertical circles are an example of where gravity combines with some other force to account for the centripetal force.  Remember "centripetal force" is another word for NET force when going in a circle.  

With any remaining time, you may start 📖 textbook circular motion problems from the next post.

Optional Extra Practice:  If you need extra practice on easy UCM problems, Circular Motion Practice worksheet (Ans:  1. (a) 8.77m/s2 (b) mass times 1a.  2. (a) 1.56m/s (b) mass times 8.11m/s2  (c) 8.11m/s2.  3. (a) 0.650 (b) no change.   Hard Circular Motion Problems.  (skip #9) ANSWERS.   - note: for #3a, an acceleration of “1g” is 9.8 m/s2, so an acceleration of 0.050g is (0.050)(9.8 m/s2).   

Homework:  Finish rest of Formative Circular Motion by 10pm tonight - Wednesday December 18th.  If you missed class or would like to review, check out these videos on vertical circles: 

💚 5: Th 12/19 - 📖 circular motion problems

Today, we'll start class with one quick Orbit Problem, which combines the ideas of uniform circular motion with universal gravitation. 

Then, we'll do 📖 textbook problems from Chapter 6: #13, 16, 21, 23, 49, 50, 61, 62, 63, 67, 69, 73.