Question about gravitational attraction
So the formula is F=Gm1m2/r^2. Could you substitute one of the mass values for an energy value since gravity attracts energy ? Or would this require a different equation?
View ArticleAtmospheric Pressure Problem
If I hold the top end of a straw filled with water, the water stays in the straw which is due to the atmospheric pressure. How come this effect is not seen in upside down cups? Should the atmospheric...
View ArticleArc of rope flowing over drum
This is a problem I thought up. If I'm correct as far as I've gone, the answer is rather surprising. A thin but 'massive' rope lies coiled on a floor. Treat the coil as a point. One end passes...
View Articleinduced electric fields
Hi all, I am looking into induced electric fields by changing B fields inside layers of dielectric. For example, if a block of several layers of a dielectric material is placed inside a capacitor...
View ArticleDifference between wavenumber and wave mode?
Are these two, wave number and wave mode, same thing? If not, what is the difference? Thanks...
View ArticleImaging through fersnel lens?
I have a Fresnel lens which is equal-ant to a Plano Convex lens, Consider object on one side and my eye is on the other side of the lens, when I see through that lens I always do see an upright image...
View ArticleWhy is the magnetic field outside a toroid 0?
Finding the magnetic field for a straight wire using the right hand rule shows that the field is around the wire. Applying this same concept for a toroid, the magnetic field inside is central to the...
View Articleexperiment - beer bottle and ping pong ball
Hello. I have a question about experiment. You know it. You need beer bottle, water and ping pong ball. You completely fill the beer bottle with water and you take the ball on the top of the bottle....
View ArticleResultant of Three Forces and a Moment?
I'm looking to find the resultant force of three forces and a moment: Fx, Fy, Fz, and Mx. I intend to graph multiple resultants. Would I just need to do the following to find the magnitude?...
View Articleprogressive waves
i was told that progressive waves has no nodes, why is it so? can anyone here explain please?
View Articlewater springs - experiment
Hello. Have you ever seen this experiment? https://www.youtube.com/watch?v=K9jRztEQ06o OK, i know why does the watter flows without cover and does not flows with cover. However, what about the springs?...
View ArticleHow to get capacitance from potential FEM
Hi guys, I hope this is the correct section otherwise I apologize :).The goal is to find the capacity of a non linear capacitance composed by an upper plate which has a cup shape and the lower plate...
View ArticlePotential Energy of dipole in external electric field
Why do we take Θ=90° for calculation of potential energy
View ArticleSpecific Heat Capacities in co-ordination with Thermodynamics
Please help me qualitatively in the following points : 1) If in a system(consider a cylinder) fixed with a piston , if the piston is moved suddenly then how can a process be adiabatic. 2) I understood...
View Articleheat emission of heating pipe
Hello! It has been years since I had physics at uni, and I have forgotten lots of it, so I need some help here. The issue concerns the underfloor heating pipes and how to reduce loss. Most conventional...
View Articlerotational frictions relationship to surface area
Hi, I have a question I'd like some help with which is related to my job working with drill rigs. Where you have a cylinder such as a drill string where the forces of the ground pressing in from all...
View ArticleThree or more isolated elastic point mass in the universe
hai friends, i would like to know what would happen to three isolated point separated by infinite distance are attracted by gravity after collision? similary for four , five and so on... number of...
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Impact of trolley - hand calculation method!
Hello, Been a while since I posted on here, nice to be back :) . I just want some pointers as to the methodology for an impact load case that I'm looking at. I've attached a very basic sketch of a...
View ArticleSimple Harmonic Oscillator on a smooth surface
I feel I understand what happens, and how to solve the equation of motion x(t) for a mass attached to a spring and released from rest horizontally on a smooth surface. We typically end up with [itex]...
View ArticleEntropy change with elevation
I have seen in a number of thermodynamics lectures that the entropy change of a system as it falls approximately isothermally from some height h to the ground is: ΔS = mgh/T (The proof basically has...
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