Relative Definition and 1000 Threads

So an extreme case ….. A cluster of matter and space, in direction of motion will be to us a huge huge disk with thickness of say 1 millimeter due to length contraction , traveling straight past the earth at velocity essentially c (very very very very close to c) However, relative to this...

Hello! I read Landau & Lifshitz' Classical Theory of Fields [Link to copyrighted textbook redacted by the Mentors] (see pic below) and I was confused when I saw in proof that coefficient "a" between spacetime interval (ds)2 and (ds')2 can only depend on the absolute relative velocity between...

Lets just say for the sake of argument that the earth, sun, solar system, galaxy were all moving due north at 1,000,000 miles an hour. If you were to travel due south at 1,000,000 mph you would basically be not moving at all. How would this affect time for you or anyone observing you?

A bag contains ##4## red balls, ##3## green balls and ##2## blue balls. A random ball is selected from this bag. P(ball is red) = ##P(R) = \frac{4}{9}## P(ball is green) = ##P(G) = \frac{3}{9}## P(ball is blue) = ##P(B) = \frac{2}{9}## P(ball is not red) = ##P(\neg R) = \frac{3}{9} +...

For this problem, My working is (a) ## \Delta t = \frac{a}{\sqrt{1 - b^2}}~ns ## (b) ## \frac{abc}{(1 \times 10^9)\sqrt{1 - b^2}}~m= d_1 ## (c) By symmetry, ##d_2 = -d_1## ##-\frac{abc}{(1 \times 10^9) \sqrt{1 - b^2}}~m= d_2##, however, I'm not sure whether my explanation for (c) is enought...

Here are two similar, quite simple thought experiments, followed by assumptions on final clock readings. In the end, my most important question to them. Exp1: - we have two space ships, ss1 and ss2, both have clocks on board, named cl1 and cl2 - we have a third clock, cl3, somewhere located in...

"The fossilized find, first uncovered two decades ago, suggests that early humans regularly walked on two feet some seven million years ago. This new analysis, published today in Nature, makes a strong case that Sahelanthropus tchadensis, a species that lived during the critical time when our...

Assuming dark energy is fairly, uniformly distributed through out the cosmos, how strong is it, or how much energy is associate with it, out in the deepest, emptiest voids in space? I'm specificlaly refering to the great voids in between the great walls of galaxy clusters. I'm making the...

Simple question for you guys. Thanks in advance for the help. If you are standing on earth with a watch and hypothetical crafts to your left and right instantly take off 180 degrees apart at the speed of light, at the 1 second mark on YOUR watch they will be 372,000 miles apart. From YOUR...

Can you explain with example what mean rotation is absolute and linear motion is relative?

(Please refer the image below. ) The velocity of Nick ##v_N=\omega r## and the velocity of John ##v_S=\omega R## is depicted. The relative velocity of Nick with respect to John will be ##v_{NJ} = \omega (R-r)##. The velocity is along the tangent to the circle centred at B. If Nick were to move...

I understand that this is the new big project for NASA.

I think that yes but how to explain it when someone standing on a ground sees them moving paralell? If I move properly, I can see two cars moving paralell ralative to the ground crashing, while someone on the ground do not see them crashing. Is it consistent?

Can a photon ever be motionless relative to the earth's surface? Did it accelerate from 0 mps to 186,000 mps?

For some reason I'm having trouble understanding relative velocity problems. I know how to solve this, but I keep guessing at random methods until my answer matches the solution in the textbook. I solved it correctly by breaking the velocity of the ball into x- and y- components, then solved...

The official solution says ±25.4°, but I'm having trouble reproducing it. Here is my solution: 1) The components of the velocity of firework F with respect to the ground G in the moment of explosion are the following (Notice, I'm using sin, because the statement says 30.0° from vertical.)...

I was able to solve this question successfully by utilizing the sine and cosine law however my instructor said I was only allowed to utilize the vector component method, I am unsure how to complete this question using the vector component method as we have two unknowns(those being the angle of...

So far I have this: vbwx= 4.40c0s(28) = 3.88496409 vbwy= 4.40sin28 = 2.065674876 vpwx= 4.4ocos28 vpwy= 4.40sin28 +2.02 Find Square root of vpx^2 + vpy^2 = 5.43? Im confused as to whether we add the 2.02 to the sin28 or the cos28 though, did I do it right? Also, not sure how to find the...

I have a disk traveling on the inner blue track (let's say the blue part is the center of the disk). I want to push the disk outside (as the disk is traveling in a circle) to the outer track. The black part is the wall separating the tracks To that end, I've made some calculations, but I have...

I think the question is wrong. My answer : But it should be wrong because : I think the question is wrong … But I'm not sure …

vcanoe_wrt_ground = 3 m/s + (-6) m/s = 3 m/s - 6 m/s = -3 m/s Thus, if I understand this correctly, the rower will never reach his goal 36 m away as his canoe's resultant velocity is negative (i.e., his canoe is effectively going downstream even though it is trying to go upstream). My only...

I've been thinking about this for a while, and thought it would be nice if someone could guide me to an answer. In Newtonian mechanics, an inertial frame is coordinate system that's able to make measurements with respect to some imaginary axes attached to it. It's a well known fact that velocity...

Hello! I was studying odds ratio and its relation to relative risk. By what I understood, the statistics that is indeed important for us and that have a nice interpretation for the context is relative risk (I was also wondering if odds ratio has any interpretation). But relative risk sometimes...

Hello! I have a question about aerodynamic drag. It sounds simple but when trying to understand why the relative velocity can be used in calculations I have some trouble. The formula is 0.5*rho*u2*cd*A where u is the relative velocity between the object and the fluid. The cd value depends on the...

I'm trying to understand this paper (equation 2.16 specifically): Bini, D., Carini, P., & Jantzen, R. T. (1995). Relative observer kinematics in general relativity. Classical and Quantum Gravity. Am I correct in reading there is no way to express the relativistic relative velocity composition...

Fossils of a new jellyfish relative from 635 to 541 MYA has been found in the Charnwood Forest, a hilly area of Leicestershire in central England. This is a place where Ediacaran (PreCambrian) fossils have been found before and where David Attenborough would look for fossils as a kid. Guess he...

Hello everyone! I'm reading this book and trying to get a more concrete understanding of friction and it's relation to Newton's third law. So in the solution he writes$$D - f - F_R = m_ta_x$$Where D is the driving force of the truck, f is the frictional force of the box on the truck, and...

Hello everyone, I have a question about calculating Relative humidity. If I have a surrounding with 30 degrees Celsius and RH of 30%. I am cooling the surrounding with an air conditioner that works at 15 degrees Celcius. At the end of the process, the room reaches 25 degrees Celcius. In this...

I was looking at that other topic, and got to thinking about examples that I believe can be shortened without any general loss in meaning. "During the election, she suspected (that) her opponent had engaged in foul play." "She soon discovered (that) her opponent had done something (that) his...

I can solve this question using relative Velocity or using 2 kinematics equations. But a peer of mine, tried to do it in a different way. He substituted the above said values in the 4 equations and solved for u in terms of t and differentiated them and equated to to 0 to find a maxima. He found...

I have made a simulation of a table tennis ball being hit and landing on the table. There are 5 differential equations that are integrated to compute the horizontal position, horizontal velocity, vertical position, vertical speed and spin. by integrating 5 differential equations simultaneously...

Given the relativity concept between twin 1 and twin 2 what is the difference between relative motion and 'relative' acceleration? Are not either twin experiencing the differential between them as a consequence of acceleration. When twin 1 instigates motion relative to twin 2, a moving carriage...

Two spaceships are heading towards each other on a collision course. The following facts are all as measured by an observer on Earth: spaceship 1 has speed 0.74c, spaceship 2 has speed 0.62c, spaceship 1 is 60 m in length. Event 1 is a measurement of the position of spaceship 1 and Event 2 is a...

Assuming that the observer moves along the direction of the light, does the speed of the observer's measuring instrument relative to the light source (which may be close to the speed of light) affect the brightness and/or power flux density measured by the observer? I'm not sure about this...

Hello, Hope you had a merry Christmas, :wink: In order to deepen some knowledge on the notion of relative simultaneity, I studied a graph taken from a video, and the ages of the twins being very very rounded, I decided to make precise calculations using two methods different. I would like to...

Relative humidity can be calculated if you know dewpoint and temperature - by formulae such as the August-Roche-Magnus approximation. All methods - all formulae - ignore vapor resistance (perms). Surely scientists/engineers have a way to then, as a subsequent step, bring vapor retarders into...

I was discussing in another page this topic with someone. He said it's relative in everything, meaning that energy and force doesn't count. This is obviously wrong because the fact that today we can't (maybe tomorrow we can) know which thing is moving towards the other and which not, doesn't...

Where exactly have I gone wrong? I think it is the part where I assume that the person gains the deceleration of the car, but I have no other way to proceed in this case. Also please only use the equations that I have posted below, and it would help if you would not use the equation for...

For example, If I have a constant probability of 50% to death per day (sorry for the macabre example but I find it good); Every day I wake up, I can say:"Today, at the end of the day, I have a probability of 0.5 to be live( or to be dead)!". Now, one can calculate the probability that after...

The correct answer is 5.6m, not sure where I made the mistake.

Hm I'm new to these concepts, and I want to make sure I am on the right track, would the relative condition number be: k=(x/2)((1/sqrt(x+1))-(1/sqrt(x))(1/(sqrt(x+1)-sqrt(x))). Or would I have to solve the limit as x approaches 0? Thank you.

Hello, I have a question regarding BH-curves and relative permeabilities from electrical steel datasheets. When e.g. looking at the datasheet from the isovac 330-35A there is the data for the J/H-curve. I calculated B=mu_0*H + J and mu_r=B/(mu_0*H). When evaluating this calculation pointwise...

This is one of my thought experiments where I am drawing a big blank, If you have 2 objects approaching a 3rd object from opposite directions (just enough off to avoid collision) at 75% of the speed of light, the first assumption is that each observing the other would see the other object...

Hi. I'm really stuck with this problem and would appreciate some help. For example, if i take the total intensity from the ##^2\text{P}_{3/2}## level, i get ##a+b##. Since ##b## is 9 times larger than ##a##, i get that the total intensity is ##10a##. This should then be proportional to the...

Does the position of the origin for the body’s rotating coordinate frame 1) stay fixed to the moving body or 2) does it stay fixed to the inertial frame, yet still able to rotate as the body rotates with the only restriction that it cannot translate with the body i.e. only affixed at the...

In matter of absolute rest and relative rest as per Newton's laws, one thing that confuses me. If a train or bus is moving for example, if one sets aside for a moment the rotation of the Earth and its orbit around the sun, one could say that the Earth was at rest and that a train on it was...

I have no problem in following the literature on this, i find it pretty easy. My concern is on the derived function, i think the textbook is wrong, it ought to be, ##S^{'}(t)##=##\frac {4t} {\sqrt{1+4t^2}}=0## is this correct? if so then i guess i have to look for a different textbook to use...

I tried to project one on top of another but I know that's incorrect since I don't know how of do this.