# Rotational Motion AP Practice

## Objective

Students will use rotational motion quantities to solve practice rotational motion AP problems.

#### Big Idea

Students get ready for the AP Physics 1 Exam when they work through practice problems.

## Context

Today's lesson is meant to help students review rotational motion and see how torque, angular momentum, center of mass, and rotational kinetic energy are tested in the AP Physics 1 Exam. I've chosen to do a full day of AP preparation for this unit because I want students to get prepared for the endurance and focus College Board requires. In past units I've given students practice problems for homework, but today we are going to start to simulate the environment and stress of an AP exam.

The lesson starts with students drawing a concept map of rotational motion (HS-PS2-1) to get them actively thinking about concepts covered throughout this unit. Then, students go through multiple choice and free response practice questions (SP5 & SP8) before the lesson ends with a hand signal closure.

## Rotational Motion Concept Maps

10 minutes

As students enter the room I greet each student and ask him or her to take a sheet of blank, white, 8.5" x 11" paper from a pile that I'm holding. If I'm holding the paper and standing near the door when they walk in I get the opportunity to connect with each student at the start of class.

Once the start bell has rung, I tell students that they will be using their sheet of paper to do a concept map on rotational motion. My students have done concept maps in this class before, so I quickly model an example of a concept map on the board. I explain to the students that they need to fill in the bubbles with any words that come to mind when they hear "Rotational Motion." I also let students know that they can have a second set of off-shoots if they want, and show an example of this on the board as well. My blank model that I draw on the board looks something like this.

I keep the learning environment quiet for this activity, otherwise I've found that the students are less authentic about sharing their own thoughts. Students get about seven minutes to work on their individual maps before I collect them.

I use these maps to assess how well my students are progressing through our unit on rotational motion. When I see a detailed example, I know that my pacing and instruction has been successful.

## Rotational Motion Multiple Choice Practice

15 minutes

Because the AP Physics 1 exam has 50 multiple choice questions that students must work through in 90 minutes, this multiple choice practice has 9 questions that must be answered in 15 minutes. The time allotted per question isn't an exact replica of what students will experience on the AP exam, but it's close enough to give the sense of time constraints.

I pass out a copy of the rotational motion multiple choice practice to each student, along with an equation sheet. Much like on the real exam, students are allowed to use calculators and must work individually. As students are working, I walk around to informally monitor students' progress and answer any format questions (I do not answer content questions).

As time ends, I collect the completed multiple choice practice from each student and let them keep the equation sheet for the next part of the lesson. It is my goal to grade these as quickly as possible so that the students have feedback when they return to class the next day. Also, I'd like students to be able to use these practice multiple choice problems to prepare for the rotational motion unit test.

Any questions that are missed by a majority of the students are reviewed and explained during the next day. On this particular set of practice questions, many students missed the fifth question, so this was the first topic we reviewed in the following class. The review process starts when I ask students to share why they believe two forces producing the same torque would have the same magnitude. Then, I explain to students that just because two objects have the same force, those forces could have been applied at different distances. I also show students on the front board that the torque equation is the product of force and distance, so the resulting magnitude depends on both of these quantities.

## Rotational Motion Free Response Practice

15 minutes

Because the AP Physics 1 exam has 5 free response questions that students must work through in 90 minutes, this free response practice has 1 question that must be answered in 15 minutes. I purposely put the free response practice after the multiple choice practice to simulate the transition students must make during the AP exam. Students should still have their equation sheets and calculators out from the multiple choice practice session.

The students work individually through the practice problem as I walk around to informally assess students again. At the end of the time, I collect the practice problem and have the same hope to grade these and return them during the next class period. Unfortunately, grading free response questions takes much longer since it requires me to refer to a scoring guide and give partial credit.

I choose this question because the AP Physics 1 exam requires paragraph-length responses. Many students mistakenly assume that the AP Physics 1 exam doesn't include any writing, so I try to practice this type of response as often as possible. Some students have really excelled in their paragraph-length responses. Other students are still struggling when it comes to these type of responses.

## Hand Signals Closure

5 minutes

My closure today is purposely brief, since I know that with the passing out and collecting of papers I may not have a full ten minutes left to summarize our lesson. After the multiple choice and free response practices are collected, I ask the class "How do you feel about the practice AP questions? Are you confident in your answers and abilities?" Students respond to me with either a thumbs up, thumbs down, or flat hand. A student who shows a thumbs-up feels confident in his answers to the practice problems, while a student showing a thumbs-down would feel anxious and insecure. A flat hand indicates that the student feels unsure about how he did on the practice questions.

My students give me a majority of flat hands, so I offered students some supplemental materials via my website to study rotational motion. Students can work through the tutorials offered from HyperPhysics or doing additional activities from PhET. I am not overly worried about the large number of flat hands because my students are notorious for not being confident and then doing amazingly well on assessments.