# applied

1. ### Determining length of a tube with applied pressure

Hi folks, I have a question. Imagine i'm blowing air through a duct that is capped in one side. The tube is made of plastic and has a 14mm external radius and an internal readius of 10mm. If I apply a constant pressure of 16 bar, and it takes 30 seconds for the air to come out on the...
2. ### Energy of band of d-dimensional semiconductor when voltage V is applied across

Let's say we have a one-dimensional semiconductor and I apply voltage V across it, I want to calculate the energy of a parabolic band, when a source and drain voltage is applied across it. I expect it to be $U = \Sigma_k \frac{\hbar^2 k^2}{2 m^*}f(k)$ where f(k) is the fermi function. When no...
3. ### What are the collision forces applied to the stops in a moving triple pendulum?

Hello, it's been a while since I did not use lagrangian mechanics and all this stuff and would bet it's needed for my purpose. Introduction : if I take a simple pendulum and make it collide on its origin with a stop, how much will suffer the stop ? Knowing that the pendulum is subject to an...
4. ### determine pressure applied by truck driving into wall at different speeds

i'm trying to figure out a formula to calculate the pressure of a truck pressing its bumper against a wall with the engine running at different speeds. this video shows exactly what i'm talking about: https://youtu.be/wWNE7kb3Mys the mass of the truck is ~2,500 kg, the area of the bumper...
5. ### Can Ampere's law be applied to 3D loop

Usually in textbooks Ampere's law is just illustrated using 2D loops which forms a plane. Can the law be applied to 3D loops which cannot form a plane surface within the loop? In a 3D loop which surface should we count when we count the current? In 2D case it is easy because there can only...
6. ### If applied force = kinetic friction, is there constant velocity?

If applied force = kinetic friction, is there constant velocity? Does it need more information to determine that it is just at translational equilibrium( v is constant but a =0), or static equilibrium(both v and a =0)? I know for when static friction = applied force there is no acceleration...
7. ### The Slope of a Normal Force vs Applied Force Graph

1. The problem statement, all variables and given/known data An experiment was conducted where a slider with different mass combination is placed on a board. A newton spring scale is attached to the slider and is pulled horizontally and parallel to the board such that the slider moves at a...
8. ### What is the trajectory of a moving object with a force applied to it?

What is the trajectory of an object moving at constant velocity with a constant force applied to it? I can think of two scenarios which determine the trajectory: 1) The direction of the applied constant force is in the direction of the object's velocity. The trajectory is linear and the object...
9. ### Force applied to a Hair

This question appears in "Holts Problem Workbook": In 1994,Mata Jagdamba of India had very long hair. It was 4.23 m long. Suppose Mata conducted experiments with her hair. First, she determined that one hair strand could support a mass of 25 g. She then attached a smaller mass to the same hair...
10. ### Force applied to falling object

Hey guys how are you all. Lets see, I'm not a physicist (mathematician actually, same name on MHF) but I'm involved in this discussion (some may be aware...) and would like some physics help. (This is not an assessment, tutorial, university, school etc question. Here's the scenario. (Hope I...
11. ### The First Law of Thermodynamics applied to a Cycle

Hi All, Would it be at all possible for someone to please advise me how the author arrived at this solution to the following question. Question; A linear spring, with a spring constant K = 100kN/m, is stretched a distance of 0.8m and attached to a paddle wheel. The paddle wheel then...