Tagged Questions
2
votes
1answer
107 views
Sideways motion between a vertical launch from a planet and landing [duplicate]
I saw a video some days ago (Hello Kitty in Space) of a schoolgirl successfully launching a balloon into space which later popped and landed ~47 km from launch site.
If I vertically launch an object ...
1
vote
3answers
352 views
Conservation of energy in objects at terminal velocities
In vacuum, object free falling under gravity, the sum of Gravitational Potential Energy(GPE) and Kinetic Energy (KE) is a constant. The GPE is a decreasing side of a quadratic and KE is a increasing ...
5
votes
4answers
529 views
Classical Limit of Schrodinger Equation
There is a well-known argument that if we write the wavefunction as $\psi = A \exp(iS/\hbar)$, where $A$ and $S$ are real, and substitute this into the Schrodinger equation and take the limit $h \to ...
3
votes
3answers
1k views
What is the physical meaning of diffusion coefficient?
In Fick's first law, the diffusion coefficient is velocity, but I do not understand the two-dimensional concept of this velocity. Imagine that solutes are diffusing from one side of a tube to another ...
5
votes
3answers
663 views
Why do non-Newtonian fluids go hard when having a sudden force exerted on them?
You can dip your hands into a bowl of non-Newtonian fluid but if you are to punch it, it goes hard all of a sudden and is more like a solid than anything else.
What is it about a non-Newtonian fluid ...
3
votes
3answers
712 views
Define Pressure at A point. Why is it a Scalar?
I have a final exam tomorrow for fluid mechanics and I was just looking over the practice exam questions. They do not provide solutions. But pretty much I have to define pressure at a point and also ...
1
vote
1answer
839 views
Dimensional Analysis: Buckingham Pi Theorem
I am studying for a fluids quiz and I am having a few problems relating to dimensional analysis but for the time being fundamentally I have a problem selecting the repeating variables. Like does ...
3
votes
1answer
125 views
Effect of rotation on turbulence threshold for Reynolds number?
If the significance of the Reynolds number is:
Then what is the effect of angular momentum on the transition from laminar to turbulent as in a convective vortex? Waterspouts, in particular, seem ...
0
votes
0answers
281 views
Calculating torque of actuators? [closed]
How do you calculate the torque of a brushless dc electric motor?
How do you calculate the torque of a hydraulic motor?
How do you calculate the push and pull force of a double acting hydraulic ...
2
votes
2answers
151 views
pressure exerted by fluid
If I had a flexible tube sealed at both ends and I submerged it in water (held vertical) Would the bottom half of the tube compress and the top half expand? What would the pressure in the tube be? Say ...
1
vote
2answers
236 views
Why isn't pressure used for flight?
Why isn't pressure used as flight?
I've heard that 2L bottles can hold a pressure of up to 90 PSI safely. Since $F = PA$, if the nozzle of a pressure rocket is about 4 inches squared in area, that ...
7
votes
3answers
451 views
Boundary layer theory in fluids learning resources
I'm trying to understand boundary layer theory in fluids. All I've found are dimensional arguments, order of magnitude arguments, etc... What I'm looking for is more mathematically sound arguments. ...
3
votes
1answer
156 views
How can you tell a model explosion from the real thing?
Movies and TV shows frequently show buildings being bombed, cars blowing up, etc. Frequently these are really explosions of miniatures filmed up close.
Aside from the speed that the explosion ...
11
votes
2answers
430 views
How to model/simulate pressures and flows in a network of pipes
I'm having a hard time finding information on how to model/simulate this. I attached a couple files, both of which show an example tank & pump network. It's just nonsense that I made up for this ...
7
votes
1answer
574 views
Pendulum with water dripping out
Consider a pendulum, consisting of a string of length $l$ tied to a ball of negligible mass and radius $r$. The bob is filled with water, which has density $d$, and the pendulum is given a small push ...
10
votes
3answers
502 views
Which direction will Coriolis forces deflect a bubble?
If I throw a ball straight up, it deflects slightly to the west due to Coriolis forces. If instead I watch a bubble float up in water, is the bubble deflected west, east, or neither?
I think the ...
