# AT Cycle 7

## 10/13 - 10/18

Th 10/13

F 10/14

M 10/17

T 10/18

### π΄ 2: F 10/14a, π‘ 4: Th 10/13 - torque meterstick lab (1)

Daily Check-in #7: Static Equilibrium - component of force method

Today, we'll apply the concepts of torque and static equilibrium to find the mass of a meterstick. If you still need help here, review the following video.

Lab Safety: Be careful when handling metersticks that you do not swing into someone else. Make sure that you handle masses with care and do not drop off the table as they could hurt you if they fall on you. Always follow your teacher's directions to use the equipment exactly as outlined.

Handout: Torque Meterstick Lab

Homework: QUIZ on energy and momentum Friday, October 14th (no torque).

In case you miss class, you can do the above lab by using some materials you have at home:

• a ruler (at least 30cm) or meterstick or a long uniform stick that you can measure or put evenly spaced markings on. (Whatever you use should be as inflexible as possible, a metal or flexible ruler will probably not work.)

• something thin that you can balance the ruler on (I used a round pencil taped to my desk, but you could perhaps even use your finger).

• some coins or washers of known mass (the heavier your ruler, the heavier/more things you'll need) - you'll need probably 8 of the same type.

• some tape to secure the coins or washers to the ruler.

Simulation Alternative: PhET Balancing Act - Part 1 can be done using this simulation if you do not have the materials. You'll have to partner with someone in your lab group for part 2 if you don't have physical materials.

### π₯β 2: F 10/14b, π¨β 4: F 10/14 - torque meterstick lab (2)

QUIZ on energy and momentum TODAY.

We'll spend the remaining time on the torque meterstick lab in the above post.

Homework: Finish your write up for the Torque Meterstick Lab. It will be collected on in your lab notebooks in class on Tuesday. Watch the following video on using the line of action method to solve Static Equilibrium Problems. Also, read the following webpage on Vector Multiplication. Remember that to calculate torque, we use a cross product. Review the right hand rule.

### β€οΈ 2: M 10/17, π 4: T 10/18a - static equilibrium problems

Today, we'll try the Hard Torque Problems for practice with static equilibrium. For the first three problems, try using the component of force method. For problem 4, check the video above to review line of action. We will continue working on this worksheet next hour as well.

1. T3 = 250N, m = 40kg
2. T2 = 3700N, Fhy = 2350N down, Fhx = 1850N right
3. T2 = 600N, Fhx = 520N left, Fhy = 50N up
4. T1 = 289N, Fhx = 289N right, Fhy = 350N up
5. Fwall = 727N, Ff = 727N, Fground = 1230N
6. 51.3 degrees (there's a typo, it should say "minimum angle")

### π 2: T 10/18, π 4: T 10/18b - static equilibrium problems

Daily check-in #8: Static Equilibrium - line of action method

Today, we'll try the Hard Torque Problems for practice with static equilibrium. Try practicing the line of action with the last 3 problems. Think about when you should use the component of force method vs. line of action method for solving static equilibrium problems!!!