# Physics 10-19-11 Equilibrium

PHYSICS: So how is the balance in your life? 🙂 Here’s the lecture from Thursday on net force, equilibrium, and equilibrants. Were you experiencing a little déjà vu? Let’s explore that a bit more tomorrow, and then ACT prep on Friday.

Image source phoenix.fanster.com/…/2009/08/tug-o-war1.jpg

## 21 thoughts on “Physics 10-19-11 Equilibrium”

1. Sebastian G. P5 says:

Ms. Skinner
Concerning the demonstrations in class today, would there be an angle at which there is no downward force, thus meaning that one would be unable to hold himself up; perhaps horizontally?

2. Matthew D P5 says:

Do we have SITN this week? I didn’t see it on the syllabus.

• Jackson W P5 says:

We don’t have SITN because of the ACT. She’s giving us a break.

3. David N P5 says:

so equilibrium is a state of stillness even though forces are acting upon an object.

4. Courtney H P5 says:

i am pretty sure we do not!

5. Jackson W P5 says:

Will someone please do the equilibrium lab with me? Ms.Skinner said someone needs come to help me with the force table. Let me know who can help.

• Megan G P5 says:

Jackson! Courtney, David, and I need to finish doing that lab… we hardly started. Come do it with us!

• Ms. Skinner says:

Megan – Thanks! 🙂

6. Jakin D P5 says:

Is the mass of the woodpecker’s head on that second worksheet just a red herring? Our group couldn’t find where it factored into the problem.

• Andrew F P5 says:

I was wondering the same thing, because I worked the problem without using the mass of the head anywhere in the problem and still got the correct answer.

7. Charlie M P5 says:

Could we go over both homeworks tomorrow in class?

• Ms. Skinner says:

Charlie – We are!

8. Cory A. P5 says:

When doing these equilibrant force problems does it matter whether we convert kg to n at the beginning or the end of the problem? Will our rounding make our answers different

• Ms. Skinner says:

Cory – 1) just convert when/where ever you need it. 2) yep!

9. Zach C P5 says:

On the newest worksheet, does the length of the wires factor into the equation maybe to give one twice the resultant?

10. Courtney H P5 says:

Is the balloon take home lab due tomorrow?

11. Cory A. P5 says:

I figured out zorba after messing with if for about 3 hours. The right angle would be at the the top of the ceiling and the two cables are come down forming the legs of the triangle from there(just like this symbol: ^ ) Since one cable is twice the tension of the other, it is a 1 2 sqrt 5 triangle. So by using tangent, u can determine that the two angles are 27 degrees and 63 degrees [arctan(2) and arctan(1/2)]. Then just plug in the angles and the f2 = 2f1 equation into the equation we had in class and you get one of the resultants. Then you can plug in that into the f2=2f1 and get the other resultant. That’s how I did it. I don’t know if there is an easier way, but this one seemed to work for me. I didn’t get 1.36×1.36×10^3 though. I think that may be a typo. I got 680 and 1360 though which seems very close

• Kamren J P5 says:

Well, Cory, you can explain this to me tomorrow sometime… I am still way confused about this one…

• Matthew D P5 says:

how do you know that it’s a right triangle hanging from the ceiling?

12. Matthew D P5 says:

how do you know that it’s a right triangle hanging from the ceiling? Good job though

13. Cory A. P5 says:

You can try a right angle like we did in class but then the cos and sin are switched. Idk if you’ll get the same answer. Like I said this is how I did it. There may be other ways of doing it.