# Tagged Questions

Applies to questions of primarily educational value - not only questions that arise from actual homework assignments, but any question where it is preferable to guide the asker to the answer rather than giving it away outright. Please READ THE GUIDANCE IN META before asking homework questions.

1answer
202 views

### a metal bar on a pair of conducting rails that carries a current

This is a homework question, and I solved it already, but something bugs me. So the problem is stated as following: A metal bar of mass M sits on a pair of long horizontal conducting rails separated ...
1answer
173 views

### New to physics and need some help with understanding acceleration [closed]

The free fall acceleration of an object under earth's gravity is directed toward? When the same amount of force is applied to two different masses, the smaller mass will be accelerated ____ than the ...
3answers
720 views

9answers
10k views

### What's the core difference between the electric and magnetic forces?

I require only a simple answer. One sentence is enough... (It's for high school physics)
1answer
785 views

### Finding the Electric Field (and other information, besides)

The problem I am working on is: Two parallel plates having charges of equal magnitude but opposite sign are separated by 29.0 cm. Each plate has a surface charge density of 33.0 nC/m2. A proton is ...
3answers
1k views

### Why isn't average speed equal to displacement over time?

I'm in an introductory Physics course and I need help! During a one-hour trip, a small boat travels 80.0km north and then travels 60.0km east. What is the boat's average speed during the one-hour ...
2answers
331 views

1answer
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### Mean value of the force in a collision problem

I have the following problem: A point with mass $m$ and speed $v$ collides with a fixed obstacle and penetrates it, stopping in a space $\Delta x$. Calculate $\Delta t$. I understand the way my ...
1answer
383 views

### Internal forces in a truss and its geometry

I'm to work out the internal forces in a truss, but I can't get my head around the geometry of the truss itself. I'm starting to think there may have been information on the diagram which I missed. ...
1answer
189 views

### Component of force field tangent to a curve

I recently had to solve the following problem: A force $F=10\hat x- 8\hat y$ is applied to an object that is constrained to travel towards increasing values of x along the path defined by $y=x^2$ ...
1answer
252 views

### Shift operator (integral calculus involving Hermite polynomials) [closed]

I didn't know whether to pose this question on Physics.stackexchange or Math.stackexchange. But since this is the last step of a development involving the eigenfunctions of an Harmonic oscillator and ...
0answers
117 views

### Number of microstates of discretized paths

Let us consider a square grid, which has been rotated by 45deg. On this grid we deﬁne a path, the directed polymer, which starts at the origin ($t = 0$) and extends in the positive $t$-direction ...
2answers
1k views

### How much work is done when pushing against a brick wall?

So this is one of the questions on my physics assessment and I would like to know how to calculate how much work is done when pushing against a brick wall. My teacher has told me the calculation is: ...
0answers
235 views

1answer
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### Is it necessary to know initial y velocity to solve this projectile motion problem?

A marble is launched horizontally off a 93.0-cm high table causing the marble to land on the floor 1.85 m from the base of the table. a.) How long was the ball in the air? b.) With what ...