2D Forces

Documents you may need:

Statics & Dynamics

Hanging Sign Lab with force probe (pdf or google doc)

Hanging Sign Lab with force scales (pdf or google doc)

If you were absent for the lab you can complete an ALTERNATE lab (pdf or google doc)

Static Sign Practice Worksheet (pdf or google doc)

Dynamics (Incline Plane) Lab with motion detector (pdf or google doc)

Torque & Center of Mass

PhET Torque Balance Lab Simulation (google slides)

Torque Lab Challenge (pdf or google doc) Hints below

If you were absent complete the Torque Lab Challenge ALTERNATE (pdf or google doc)

Torque Worksheet (pdf highly recommended over the google doc)

Centripetal Motion & Universal Gravity

Spinning Lights Observations (pdf or google doc)

Circular Motion Lab (pdf or google doc)

Direct Measurement Centripetal Force Lab (pdf or google doc)

PhET Gravity & Orbits Lab Simulation (pdf or google doc)

Extra Practice:

2D Motion Study Guide & Puzzle (pdf)

2D Motion Partner Review Worksheet (pdf or google doc)

Circular Motion (pdf or google doc) but don't check the answers until after you try it!

Hanging Sign Help (pdf)

2D Motion Help (pdf)

Incline Plane Help (pdf)

Homework Hints:

Torque Challenge

I've gotten a lot of emails asking about the Torque Lab Challenge. I'm hoping this visual helps; it is made of the equation on the first page, your data table and the picture underneath step #16:

Statics Practice worksheet

1. If you sum your forces there is only one Force of Tension working against gravity. (~30)

2. If you sum your forces there are two Forces of Tension working against gravity. (40)

3. If you sum your forces there are four Forces of Tension working against gravity.(~30)

4. Find the vertical component of the Force of Tension by summing your forces in the vertical direction. Use trigonometry to find the Force of Tension along the rope. (<40)

5. Since you are given the Force of Tension work it backwards from #4. First find the vertical Force of Tension component using trigonometry and then sum your forces to find the Force of Gravity. Use the Force of Gravity to find the mass (<40).

pg. 135 #38a and 40

38. Do (a) only!You are given the Force of Gravity and you will need the mass so find the it using Fg=mg. Find the Fgx using sine; this is the force that is pulling it down the plane. Since there is no Force of Friction mentioned, this is the only force in the direction of motion and is equal to mass x acceleration. Solve for the acceleration (<5).

40. You are given the mass and must solve for the Force of Gravity (>400). Find Fgx (>300) and Fgy (>300). Find the Normal Force now that you have the Fgy and use that to find the Force of Friction (<80). Sum the two forces in the direction of motion and divide by the mass to find acceleration. (>5)

pg. 140 #61, 62, 64, 65, 77; pg. 134 #34, 36

pg. 140 is conceptual - refer to your notes and the Chapter

34. Given the mass of the glass, find its Force of Gravity. Remember that the Force of Gravity can be broken up into parallel (Fgx) and perpendicular (Fgy) components. Draw a triangle to help you out; the Force of Gravity is always straight down. (>1 for both)

36. As the kid moves down the banister, his normal force is equal but opposite to the Force of Gravity in the y direction only. Use his mass to solve for the Force of Gravity and then use cosine to find Fgy. Use that (and the fact that ay = 0m/s^2) to solve for the Normal Force. (<400)

Torque Worksheet

4. You have multiple torques going around the pivot point which is the bottom bolt. There is a Torque from the top bolt 3m away and another torque due to the Force of Gravity half the length of the sign away.

Mobile - Start from the bottom! READ the instructions at the top of the page. Balance the Torques of the first horzontal strut and determine where you will hang it. Since the masses are equal, you should hang it from the center of that horizontal strut. Then, add the masses as this will become the new perpendicular force for the next horizontal strut. For each strut, you know the force and distance on one side so that you can calculate the Torque. In order to be balanced the Torque on the other side must be the same. Given that force find the distance.You will end up with angled connnections, which doesn't look realistic, which is why you must redraw the mobile at the bottom of the page.