# Search results

1. ### KCL and First order circuit theory

My question applies to the case when the switch opens. By applying KCL in order to get a first order diff equation, the following problem arises when I choose different current directions (which shouldn't happen because KCL says the current direction doesn't matter because it will be fixed...
2. ### Griffith's 3.33

I am "continuing this thread" in hopes of asking questions that deal with the meaning of the question. https://www.physicsforums.com/threads/griffiths-e-m-3-33-write-e-field-of-dipole-moment-in-coordinate-free-form.359973/ 1. Homework Statement Show that the electric field of a "pure" dipole...
3. ### Why do the face diagonals have different angles?

Homework Statement Find the angle of the face diagonals of a (unit) cube. I agree with this solution, but I have a problem with another face diagonal: the face diagonal from the angle (0,0,1),(0,0,0), and (1,1,1). Homework Equations dot product cos-1(a.b/ (|a||b|) The Attempt at a Solution...
4. ### Norton's Theorem

Homework Statement Find Io using Norton's Theorem Homework Equations The Attempt at a Solution I broke it into the following circuit: I would like to break it down some more but if I open the node between 3k and 6k (ohms), and 6k and 6k (ohms), I run into problems.... What should I do...
5. ### Given a piston find pressure

Homework Statement Find the gauge pressure of a piston-cylinder system, assuming that the piston perfectly covers the cylinder. The piston's radius is 5 cm, its mass is 3kg, and the force being applied to it is 75N in the same direction as gravity. Looks like this picture...
6. ### Engineering Engineering or something more?

I am a freshman mechanical engineering. I have been exposed, to some extent, mechanical/materials, robotics(electrical), and I'm headstrong about not doing civil. I considered computer science, but I'm glad I didn't because it seems that not much calculus (math) is required for the major. I...
7. ### Acceleration does not matter when driving

In my physics lecture, my professor "proved" that acceleration does not affect the amount of energy used in driving a car. Assume car is driven along flat road. In the short, (assume air resistance is neglected, and the W done by the car's engine, W_{engine} is non conservative, \Delta PE...
8. ### Textbook made mistake in algebra, help

Homework Statement There is an image but I will reiterate my problem. The writer is solving for t. Okay, easy enough. Homework Equations y-y0 = v0 t + 1/2 a t^2 Textbook says t = sqrt( (2(y-y0) - 2 v0) / a ) The Attempt at a Solution Shouldn't it be t = sqrt( (2(y-y0)...
9. ### Dimensional Analysis: Inverse Cosine

Homework Statement For the following dimensional equation, find the base dimensions of the parameter f: M M-3 = a cos( f L ) Homework Equations M represents mass, a represents acceleration due to gravity, in terms of mass * length over seconds squared [[M * L]/[t2]] where L represents...
10. ### Freshman schedule help: advanced physics & chem? calc3/lin.alg/diff.eq

I am going to be an incoming freshman for engineering (undecided, big 4). I am building a schedule that I don't know how to build. Scored 5 ap calc bc. *** My schedule list is * **English**: Freshman Composition (Honors maybe, i dont think this matters much) * **Math**: Calc 3/Lin. Alg...
11. ### Programs Free online introductory classes good method of choosing an eng.major?

I am an upcoming freshman. I will major in engineering. When applying to the school I chose mechanical because of its "versatility and stability in the job market." (I don't fully understand the meaning of these phrases; I get my knowledge from anecdotal experience when browsing forums). I may...
12. ### Set Theory: Why use implication?

Homework Statement I hope this does not violate copyright or anything but this problem originated from an assignment from Introduction to Mathematical Thinking in Coursera. I could not post there because the class ended and the discussion board there is dead. Let C be the set of all cars, let...
13. ### Organized way of setting up (introductory) physics problem

I did not post this on the homework forum because they required to use the template. First, I have been using the "Known____Unknown______Equations" format; however, I feel this is not organized well enough for me. Then, I tried "Variables____Components_______________Equations" format. Do...
14. ### Where did the radian come from (Torque)?

In the simple torque equation: \tau_z = \alpha_z \times I \frac{\tau_z}{I} = \alpha_z Finally: \frac{10 N.m}{10 kg.m^2} = \alpha_z \frac{10 kg.m^2}{10 kg.m^2.s^2} = \alpha_z 1 \frac{rad}{s^2} = \alpha_z