# Search results

1. ### Determining the path of a particle in a field

This is not a specific homework question, but more of a general query. If provided with a simple vector field indicating forces (for example, an electrical field), can you use integration to determine the path of a particle placed in that field, if also provided with some initial conditions...
2. ### Simultaneous heating and cooling

Nugatory, So, if I have what you are saying right, I am starting with dT/dt = -kT(t) + kTroom + c where k is a constant for cooling and c is a constant for the heating rate [as it is not affected by the temperature difference]. This seems to show that the rate of cooling is proportional to...
3. ### Simultaneous heating and cooling

I am having trouble wrapping my head around a particular problem I am thinking about. Consider that I have a heating source that I can describe in terms of either degrees Celcius / second or Joules / second, but essentially I am able to determine a fixed heating rate. Let's say: dT/dt = 5...
4. ### How to resolve the heating and cooling of an object?

Perhaps I'm not completely understanding what you are saying, and my apologies for that. The law of cooling seems to first assume you are at some temperature above Tenv and then will cool down - in the absence of any other heat in or out of the system. (If i am wrong in this, please let me...
5. ### How to resolve the heating and cooling of an object?

I am not sure how to proceed. This is just something that i have been thinking about and would love a little help with. Lets say I have a situation where i am increasing an object's heat energy at some specific rate - for arguments sake, it's 2 degrees every second. If you like we can also...
6. ### B Franklin bell question

yup - that's what i thought. good point on the assumed neutrality of the ball too.
7. ### B Franklin bell question

hello all so i have been messing about with a homemade franklin bell. It is being charged with an electric fly swatter. I have been wondering if the neutral ball a the center should have any preference as to which side it would be attracted to FIRST. In my head i think it should not matter...
8. ### I A model of what makes up the physical world

you can see problems arising really quickly with this sort of diagram. Consider a student asking " ok - if there is force and matter - what is a force if there is no matter?" the diagram suggests this. the diagram suggests also there is matter without energy. I know YOU may know the specifics...
9. ### Parallel and Series Circuit

the best way i found to working out the solution was first assuming that the 100 is in a parallel circuit.then it was a matter of calculating as i went to see if i was getting higher or lower than 62.5, thus determining what had to be arranged to get higher or lower. honestly tho, this...
10. ### Equations: whiteboard vs slides

At this point we have a variety of opinions on methodology but it may prove to be a better exercise by simply picking out a single topic that would be able to be covered in a typical high school grade 12 physics class, and consider how you would put that class together, assuming you have a...
11. ### Trouble solving an equation

first off - OOPS - no we are using |sin(x)| - my apologies for the typo. i was considering a linear approximation method. separating them into the two parts seems the easiest method. thanks all. this is one of those situations where i threw out a question to my students and never checked the...
12. ### Fun experiments to disprove Flat Earth

I am producing a series of 'debates' between myself and my physics 12 students. I feel strongly that their ability to logically conceptualize their ideas and debate them is an important par of the class. Therefore i will argue against groups of four who must argue against a flat earth, moon hoax...
13. ### Determine the second derivative of a function

consider that one way of thinking about derivatives with the chain rule is that you have a function INSIDE another function. so start with the idea that a chain rule assumes you have a function of the form f(g(x)). what does the derivative look like, according to chain rule?
14. ### Trouble solving an equation

Homework Statement i am looking for the potential extrema on the function y = |sinx(x)| + (1/x) between [-2pi, 2pi] Homework Equations extrema will be likely located at f'(x) = 0 or u/d The Attempt at a Solution first it is noted that there is a discontinuity at x=0 then determining f'(x)...
15. ### Request for Advice on a Physics Lab

we have laser pointers and can likely order any other items we need. Of course, mind you, I would like to avoid the "find the n value for this substance" type of experiment which still is simply a paint by numbers type of lab. although maybe there is something there with "proving the law is...
16. ### Request for Advice on a Physics Lab

i would never expect a high school student to come up with Snell's Law, no. I can't think of how it would suddenly occur to them to see a trig relationship. So I am hoping to change the nature of the question in a way where there is still something to discover without it being a straightforward...
17. ### Request for Advice on a Physics Lab

Hello I'm trying to come up with a solid Lab to use for my chapter on Waves and Optics. I am considering having it center on refraction. Here is the problem: All labs I create for my class must avoid being a set of instructions for the student to perform. The must always be set up as a...
18. ### Trying to figure out a limit as x-->a

DELTA: this seems to take care of it - provided you know how to expand a sum of powers to a high level - had to look it up to be honest: so revised sheet:
19. ### Trying to figure out a limit as x-->a

The restriction is due to the question is apparently brought up before any derivatives are introduced. So apparently this is do-able without using straight up differentiation. Yes, the 1/3 is killing me. and i have no idea how to approach it.
20. ### Trying to figure out a limit as x-->a

it looks like I'm trying to get a derivative. I am trying to do this without working using any derivatives and for some reason the power of 5/3 is completely messing with my head and i do not know how to proceed. i am still getting a 0/0 situation.
21. ### Trying to figure out a limit as x-->a

Homework Statement the limit x->a of [(x+2)^5/3 - (a+2)^5/3] / (x-a) Homework Equations limit laws The Attempt at a Solution [/B]
22. ### Need help finding roots for a complex number using angles

ha! a simple addition mistake threw me completely off. thank you so much. everything makes sense now and i can walk away from this .content
23. ### Need help finding roots for a complex number using angles

so i am starting with the equation x3 = √(3) - i first : change to a vector magnitude = √[ (√(3))2 + 12] = 2 and angle = tan-1( 1/√(3) ) = 30 degrees (in fourth quadrant) so i have a vector of 2 ∠ - 30 so i plot the vector on the graph and consider that : 1. the fundamental theorum of...
24. ### Rube Goldberg Lab?

I was checking on this thread and sad to see no replies. Is it safe to assume that no other teacher has tried a rube goldberg type lab experiment/activity?
25. ### Rube Goldberg Lab?

certainly: This was a class against another class competition kids were in groups of 4. Groups had to work together to accomplish the goal of the entire 'machine' they were to build a section each of the entire RGM. in other words they were building their own individual group machine that had...
26. ### Rube Goldberg Lab?

Have any other teachers tried this? I put one together this last term with a reasonable amount of success. I was wondering who out there has also tried to do this and if so, what kind of parameters did you set?
27. ### Getting two Answers : calculating velocity of ball

Fantastic. The different velocities is giving me a way to calculate the actual energy loss from the impact. That's awesome. This turned out better than i thought. Many thanks for the help.
28. ### Getting two Answers : calculating velocity of ball

From what you are saying, I am taking it that the impact of the ball on the box would release some energy before it even begins to slide? Could this be calculated? I assume not without further information. However, now this leads me to even more confusion. Are you suggesting that method 2 is...
29. ### Getting two Answers : calculating velocity of ball

i think the assumption i am making is that KE + Wnc = 0
30. ### Getting two Answers : calculating velocity of ball

Homework Statement Mr. Gale decides to build his own velocity measuring machine. His plan is to build a box (mass 2.50 kg) that catches the ball (mass 0.500 kg) being thrown. It then slides across the desk but eventually comes to a stop due to friction (μ = 0.800) between the box and the...
31. ### Avoiding sunlight in school

256bits, I am referring to the sail itself. A cable can run pretty long spans. Here what I am really trying to tell the OP is that once you hit spans larger than 20 m for the sail (or for that matter, even the cable) then you are looking at a sudden jump is costs, both in materials and labor...
32. ### Avoiding sunlight in school

Thanks Evo, I had not read that in the later posts and missed that posts were not allowed for this. Sorry for not getting back to you sooner, Yashbhatt. I will post the pics here to explain myself anyway, but have to tell you that a large canopy / roof is not feasible. You will have to spend...
33. ### Integral of absolute value function

could you post your graph? I am not sure where you are deriving this equation.
34. ### Describe the motion of the rock particle at point B during t

EXACTLY just be sure you can tell which way the point DOES move.
35. ### Describe the motion of the rock particle at point B during t

thankfully you don't need a rope - use youtube! take a look. put your finger on a point along that rope. does it move forward? the wave clearly does. But what about a point on the rope? in other words, which way does the medium move?
36. ### Describe the motion of the rock particle at point B during t

Careful - I think I can see where your problem is. Consider I have a jump rope. I'll mark a spot along it. In fact if you have a rope nearby you should do this! Now lay the rope on the floor and have it stretched out. take one end and give it a quick a up and down jerk (you are making the...
37. ### Describe the motion of the rock particle at point B during t

Notice that the wave itself is moving in the forward direction. At a later moment, that entire wave will move forward (to the right). What will happen to point B then?
38. ### Integral of absolute value function

You should do the following: Graph the function. Notice where it changes from one function to the other. Notice you are looking at two triangles Now - consider what the functions are over each triangle. See if you cannot make an integral made up of two parts. Remember that when you drop the abs...
39. ### Avoiding sunlight in school

Yashbhatt, India! I lived there for a year - up near Chennai. So yes - on the hotter side (a bit of an understatement really). I would assume that you school has actual construction drawings. If the administration is asking you to do this, then I would think you could demand to see them. This...
40. ### Avoiding sunlight in school

Yashbhatt, I have about 15 years architectural experience, and could probably help you with some of the details. The sail idea seems like a good idea on first glance, but in order to really see if anything is viable there has to be more information than a photo. A few things one would need to...
41. ### Supersonic wave and distance calculation

2tts, Perhaps, but you may also put an entirely positive spin on this and consider that this makes your calculations much much easier!
42. ### Creating the student-centered lab

I must respectfully disagree. I do feel that by presenting the procedure as an unknown changes the game plan for most students. The feedback from this initial foray was overwhelmingly positive. They actual felt like scientists, and - although this is only anecdotal - all of the students clearly...
43. ### Supersonic wave and distance calculation

2tts, I watched the video, but i am not convinced that this is a sonic boom, or rather a shock wave hitting the boat. First off, what I seem to see going on in the video, is a large explosion - very very loud one - where the sound reaching the people in about 13 seconds. This is august 2014 in...
44. ### Creating the student-centered lab

ZapperZ, An excellent resource! Thanks for the link. I will be spending some time there.
45. ### Creating the student-centered lab

I had mentioned in another thread that I had just started teaching Physics. I had spoken about the qualities of a Physics teacher and the challenges he/she may face but something I left out was "The Lab". This was something that was a thorn in my side right from the start going back to when I...
46. ### Becoming a Physics Teacher

I am now finishing my first year teaching high school physics and pre calculus / calculus. Here is my current take on this job [i should mention that I am in my 40s and this is not my first profession]. I do not agree with earlier sentiments of the entitlement attitude of the kids these days. I...
47. ### Supersonic wave and distance calculation

2tts, I'm trying to understand what exactly you are trying to do. Are you: A) calculating a distance by determining the difference between when you see something and when you hear it? or B)calculating a distance by determining the difference between when you see something and a super sonic...
48. ### Starting the Sander's Parallelogram Proof

I think I should clarify what I am trying to do. I do not wish to construct the parallelogram. I want to be able to set up the initial conditions by which I could then ask someone to prove that the two bisectors are equal. By this I mean a standard two column mathematical proof. I do know...
49. ### Starting the Sander's Parallelogram Proof

Can anyone help me set this problem up? I am trying to figure out how to Prove the Sander's Parallelogram. See it here: http://www.tigel.nl/fun/files/opticals/Ill...ith_line-25.htm [Broken] basically it is proving that the bisectors are of equal length The question is: what would be...
50. ### Circuits Question : Series

I should make it clear to everyone on this thread that this entire exercise is related to finding a way to teach the idea properly to high school students. Therefore some concepts must necessarily be left out. I have found that certain analogies - the water pipe one for instance - cause more...