As I understand it, the principle is essentially that...

Galileo's experiment and a lack of understanding...]]>

Related to - Thermionic emission]]>

Light pressure energy?]]>

RH affecting atmospheric attenuation of light?]]>

My suspicion is that while converting...

How can 'd' mean to different things?]]>

But what is the model of the universe that is...

What is the appropriate time/matter model for the universe?]]>

2. young's double slit experiment...

Revolutionary Physics experiments that changed the world]]>

Spinning and the Earth]]>

is there a possible or a certain arrangement of prisms , lenses and mirrors that can be made in order to combine numerous less...

Combine lasers to make a single strong beam]]>

Time to equalization]]>

Firstly I'm sorry about language. In Turkey, Our education system does not adequately support English. Anyway.

What is the evidence about gravity is exist. Wait. I mean, we know something pushing...

What is the evidence that there is gravitation?]]>

Gallium not becoming a solid again?]]>

A frictionless pulley with zero mass is attached to the ceiling, in a gravity field of 9.81 m/s2 . Mass M2 = 0.10 kg is observed to be accelerating downward at 1.3 m/s2

and I have a solution which tells me to solve the problem use Newton's 2nd law:

m1a1 = T1 -...

Understanding Newton's 2nd Law]]>

Formula to determine effort to raise a ladder]]>

Flux = The surface integral of the field E = charge / permitivity in space (Gauss law)

The permitivity in space is:

8.85 10

So I understand the units of Flux are:

Newton meter

Is...

Elementary question on Electric flux units]]>

Lagrangian paradox]]>

Leverage and Forces on a Pivot System]]>

How far do vibrations from a vehicle emanate?Doppler effect?]]>

Could someone explain to me why an electron at rest without any influence from a magnetic or electric field cannot emit a photon ?

Could you explain it mathematically too ?

Thanks in advance...]]>

This started with a student confused with statements describing critical temperature for the gas/liquid equilibrium. Some books and sources state it is the highest temperature AT which it is possible to liquefy the gas just by...

Critical temperature, or: Is the supercritical liquid a phase?]]>

I recently came across a blog on schlieren visualization (http://ottobelden.blogspot.in/2010/07/homemade-schlieren-photography-setup.html).

I replicated it with the following: Convex lens (130 mm dia and 350 mm focal length), LED light source (5 mm white LED) and smartphone...

Velocity Estimate from Schlieren Flow Visualization]]>

Derp lol]]>

thanks.]]>

Space station artificial gravity - how to spin up to speed?]]>

Does the magnetic field produced by a magnet act on itself?]]>

Let's say we have a pitcher and a catcher on the moving walkway 80 feet apart, and the pitcher throws the ball to the catcher, and the time that it takes to travel from the pitcher to...

Observed speed of pitch different than catcher's view?]]>

D= 7300 ft = Length of the rod

J = Jm - Jf -Jb +Jten

so I am not sure how to do this ...

can...

Progressive Cavity Pump backspin]]>

So a number.

For scalars, I agree because they are described by a single number.

But what about vectors? They have...

Definition of Measurement]]>

Thank you Physicsforums!]]>

If you were to reduce the pressure in a container of liquid to 0, while also insulating it from any outside heat, would it remain a liquid or turn into a gas? If it turns into a gas via lack of pressure alone, does the...

Evaporation through vacuum]]>

I have a fluid dynamics problem which appears to challenge some momentum principles.

Suppose you have two submarines (like below), identical in shape, but not in mass. One of the submarines has density equal to the fluid, while the other is denser. They move at the same...

How is the momentum conserved inside of a fluid?]]>

Help understanding recent work on "Space-Time Crystal" and TTSB please]]>

Are many physicists not fluent in the language of physics?]]>

Difference Electric Field Strength Point Charges vs. Plates]]>

Work done due to static friction in a boat-man system]]>

A 'gravity battery' could be created by using an energy source to slowly lift a large weight (using gearing or pulleys), then discharged by lowering the weight to...

Another 'Gravity Battery' Question]]>

Force and potential energy]]>

I'm having some difficulty comprehending "normal" transmission of stress/strain through a solid body and "shock" transmission of stress/strain.

Imagine I have two bodies, one rigid - the other elastic.

If the rigid body is fixed in space, and the elastic body is flying at the...

Pressure wave vs. Shock wave in solid body]]>

I stumbled into a somewhat odd mathematical problem, so I guess I've overlooked an important detail.

If I have a mass of 1kg on wheels horizontally, and apply 10N of constant force so the mass is accellerating. I assume the velocity of that mass after 1 second is approx 10m/s. Then...

Force, mass, acceleration, kinetic energy]]>

I am in an argument with a friend, he believes that the volume of the cup could be found by holding the top of the cup right about the water...

What is the volume of a cup?]]>

Direction of momentum transfer?]]>

I was helping a friend with the problem:

You shoot protons going v=4.2e7 m/s through a particle accelerator. They collide with gas particles of an unknown mass (pretend no velocity) and all bounce back elastically at...

Why does the equation for elastic collisions work like this?]]>

Unusual gravitational observation...answers?]]>

Do photons carry magnetic force?]]>

$$U_t=\alpha^2 U_{xx}+VU_x$$

I understand that in this situation you can transform to a moving coordinate system and the convection term will dissapear and you can solve for diffusion alone and...

diffusion and convection in a moving fluid]]>

From figure below, p2 and p1 applied on plane's wings. When airplane landing/decrease altitude, wich condition must occupied

A. P1=P2 and v1=v2

B. P1<P2...

Dynamic Fluid (airplane landing/decrease altitude)]]>

Moving charges and varying magnetic fields]]>

Can anyone explain why I am getting negative result with a large Neodymium N35 ring Magnet ?

B Field of Large Ring Magnet Calculation]]>

Correspondence between entanglement and chaos?]]>

I see that it says it's based on Lenz's law, which says that the induced currents will generate a field that opposes the change in the field. So, I figure they have some kind of oscillating...

How does this hoverboard work?]]>

Now my question is :

What’s the relationship between entropy in the information-theory sense and the thermodynamics sense?

I need some clear and...

The Term "Entropy"]]>

In ceramic formulations they perform great, as expected.

When formulated in silicone rubber, they do not perform when subjected to...

microwave susceptors are suppressed in viscoelastic mediums]]>

pressure of the room) in a piston style apparatus. In this model, I am expectant that there will be a measureable change in the internal...

Programatically measure air pressure within a piston]]>

I am trying to figure out the speed I was hit at in a recent accident.

I was stationary at a junction (vehicle weight aproz 1470kg) foot on brake

was hit from behind (vehicle weight aprox 2000kg)

was hit full on driver did...

Speed vehicle travelling on impact]]>

what is magnetic force generated by planar spiral coil?]]>

Reflected sunlight]]>

Vacuum infusion bag - can external pressure help?]]>

1:[tex]

Electric field =\frac{Force}{Magnitude of charge} [/tex]

1 is The definition of electric field on a particle (?)

2:[tex] Force = \frac{Q1*Q2*K}{R^2}\\[/tex]

2 is Coulombs law, to find force between...

Voltage derivation for charged particles]]>

I'm in my first year of university, studying industrial engineering. On a test I got the following image:

View attachment 112909

The red square is...

More force with more pulleys?]]>

Ive been reading about reflections and transmission at Air water surface.

I get the idea that at the Brewster's angle dipoles aligned at the surface can not emit p-oscillations in the reflected direction as the dipole is aligned parallel to this direction. What I...

Polarisation Brewster's angle]]>

Designing cryostats]]>

Ecosystem follows the laws of termodynamics

1st law

However, in this case, I had to calculate the work done by the spring force as a function of y

View attachment 113388

Over here, I assumed the spring force, which is a function...

Why can I assume the force to be constant in this interval?]]>

im wondering if there is a video where a calculated model and the same situation in reality gets compared ? :)

e.g. water drop, or something crashing with a certain speed :)

thanks for any help :)]]>

Is it possible to travel with high speed beyond a solar system or a galaxy? Or is there something that will prevent something to move at high speed outside a solar system or a galaxy?]]>

2. View attachment 109335

Well, these are two pics on circular motion, i found on net...

If the objects had a zero rotational motion before circular motion, and the next moment suddenly a force acts ( perpendicular to their linear momentum ) such that they...

Do objects in circular motion also *have* to undergo rotation?]]>

What are we made of? (IB project)]]>

help with putting a box on a shelf (gravity?)]]>

i want in fact to distinguish between different methods to model or study or describe plasma physics .. from my read i found that there are various ways to study plasma physics one way is the single particle...

question about plasma modeling]]>

I am going to do a presentation about the bootstrap paradox in a few weeks and I need some help. I understand what the bootstrap paradox is but I need some help to sum up the theory so that i becomes easy (or at least easier) to understand. If you have any examples or facts that's fun...

Can someone explain this? (bootstrap paradox)]]>

A ball struck by a cue in billiards with English goes straight at first...]]>

Given this recent news story...

How to stop insulation from floating when flooded]]>

First stop should be our very our PF Insights blog which hosts many physics tutorials...

Physics Learning Resources]]>

I specialize in high performance solutions for Nissan vehicles. I've recently gotten into the top speed Texas Standing Mile competitions. The current champion is using a Ford GT with unknown power to set the record at 274 MPH from a still launch; I want to beat his record.

I...

How many horsepower?]]>

Orbital angular momentum wavefront velocity]]>

How fast would a car be going to throw a 50lb object 38ft?]]>

There's a message board I've found that is devoted primarily to debunking popular...

An odd question regarding Bernoulli's Principle]]>

1.

When I calculate the volunme of a sphere summing up discs of height dy from -R to +R, the error in volume tends to zero as Delta y->0 but when I'm calculating...

When exactly does error -> zero in calculus-based mechanics?]]>

For compressibility of a gas... I am having a tough time finding anything. compressibility factor I can find, which is 1 for Hydrogen... but how does that relate...

compressibility of liquid vs solid actual numbers]]>

(If it's not clear from the photo, there seems to be a air bubble trapped right under the stream)

It sustained itself for a couple minutes, took a short video of it too before it...

Saw this at work -- an air bubble trapped right under the water stream]]>

I understand how centrifugal force works - you spin something around and it wants to fly away from the center.

And I understand that there are...

Random question regarding centrifugal force.]]>

How can a glider or an airplane do a loop without thrust]]>