Speed Definition and 1000 Threads

Just recently I came up with a new idea to measure one way speed of light and/or synchronize distant clocks: Let’s have two light sources at points A and B separated by distance d and sending constantly (perpendicular to AB) signals to clocks at A’ and B’ Let’s have an opaque rod of the length...

In the wave equation## \frac {\partial^2 \psi} {\partial x^2}=\frac{1}{v^2}\frac{\partial^2 \psi}{\partial t^2}\tag{1}##, v is the speed of the wave propagation. With respect to which reference frame is this speed measured( in general)?

Homework Statement an asteroid heading towards earth, has a speed of 7.25 km/s as it passes the moons orbit, kit misses Earth by 5000km. What is the speed at the closest point to earth? The professor provided us with the solution, which should be 11.0 km/s, however when I do the calculation...

Okay...The speed of light is affected by density of the medium in which it propagates...It is more in rarer medium and lesser in denser medium...Hence we can conclude that a medium affects the speed of light...My question is that why this ''affect'' is not ''continuous'', like why the speed of...

Why does light move at the speed it does, why not half the speed or double?

I'm trying to calculate the displacement d of a plane as it accelerates towards lift-off velocity. The acceleration is given by the function a = a0 - kv2 where a0 is the constant acceleration from the plane's engine and the term -kv2 is caused by air resistance. I can't seem to find a way to...

Homework Statement Andy Roberts the former West Indian Cricket player and Fast Bowler, bowled his fastest delivery in 1975 at 159.5 km/h. Neglecting air resistance, calculate the maximum distance he could have thrown the ball at this speed (on earth!) had he been able to throw it: i)...

Why speed of light is independent of frame of reference,why is it constant everywhere, speed of an object is different from different FOR then why this is not follwed by light, In deep space there is nothing to measure the speed of light relatively, then how it got its speed(299 792 458 m/s)...

Hi, I am modelling a DC motor using Simulink. Under no-load conditions, I get a max speed of 180 rads/s, but under load, the speed goes up to 290 rad/s, although takes longer to reach max speed, acceleration decreases. I have a mechanical background so don't know much about motors, but would...

Hello. Just wondering how to calculate the sound speed in the atmosphere if I have temperature and pressure from the surface and all the way up to thermosphere?

It's generally understood that nothing can be accelerated up to the speed of light, and that nothing can surpass it. That being said, the expansion of space itself can exceed this "universal speed limit," as the Universe is expanding so fast that light can't catch up to it. Regarding the...

I had read in the Time-Life Science Library book "Man And Space" about the possibility of a very, very ambitious mission in which an astronaut would go to a galaxy 200 million light-years away, with the spacecraft simply being accelerated at 1 g during the whole time (in the direction of the...

I am studying for the MCAT and I got an interesting question from a Kaplan book: 15. A water tower operator is interested in increasing the pressure of a column of water that is applied to a piston. She hopes that increasing the pressure will increase the force being applied to the piston. The...

Homework Statement In the experiment for the determination of the speed of sound using a resonance tube, the diameter of the column tube is 4 cm. The frequency of the tuning fork is 512 Hz. The air temperature is 38° C in which the speed of sound is 336 m/s. The zero of the meter scale...

I'm modelling the Hiroshima nuclear explosion on a real time real scale physics simulator. My initial simulations based on data accumulated from wikipedia such as temperature of the fireball the radius of it and using air pressure and air density data based on the detonation height of 600m has...

I am doing a review for a Dynamics exam, but I am having trouble with this one question (below). Please note the top of the picture contains the answers. What I have done is make a free body diagram that includes the tension of the cable and the weight of the rider/swing. So according to my...

Homework Statement A uniform disk of mass M = 3 kg and radius r = .22 meters is mounted on a motor through its center. The motor accelerates the disk uniformly from rest by exerting a constant torque of 1 n * m What is the time required for the disk to reach an angular speed of 800 rpm...

Homework Statement I have a task right now that requires me to calculate the energy savings that would be made by using a variable speed drive. Question: The factory process water distribution system consists of a 150mm cast iron ring main at a pressure of 5 bar (50m). The local water is...

1. Ut will bungee jump from the golden gate bridge. The height that she will jump from is 65 meters. The rope pulls her up 8 meters above the water. If UT's weight is 63 kg, how far will the rubber rope pull her upwards, if there's no loss to friction or air resistance? Homework Equations...

The spacecraft "Helios 2" (with 100 kg of mass) used the Sun to get a speed of 250.000 km/h using gravitational assistance, I want to know if the mass of the spacecraft influences the result of the speed. I mean, if the spacecraft mass 10.000 tons, the speed would be less of more?

Homework Statement A tank with a 25.5 litre capacity contains air compressed into 355 atmospheres used to drive a torpedo by expansion into an engine via a pipe of diameter 0.08cm. A mechanism ensures that the gas flows to the engine at a constant rate and any cooling of the air during...

Actually that's very easy question but I have some difficult to understand the logic behind . So-"The initial velocity of an object (m/s) is Vi=1i+5j+2k. And the final velocity is Vf=3i+5j+7k. What was the change in speed of the object?"X Solution - |Vf|-|Vi| = √(32+52+72)-√(12+52+22) = 3.63...

Homework Statement In this part of the lab you tracked a single peak as you moved a microphone in order to get a good value of the speed of sound. This question will lead you through a similar process with just two measurements. (The lab set up: speaker emitting the signal faced one microphone...

Homework Statement A body moves in a straight line along the x-axis. Its expansion as a function of time is: Given that at the moment t = 0 its speed was v0 in the positive direction of the x axis, and its position was at x0. 1. the body velocity in meters per second has a given moment t0...

Homework Statement A comet moves around a stat in ##xy## plane along elliptical orbit, described by $$ 0.16 x^2 + y^2 = 4 $$ where ##x, y## are in ##AU## 1) Sketch the comet in the ##x,y## coordinate system denoting all orbit parameters 2) Find the semi major and minor axes of the orbit...

Homework Statement A submarine engine provides maximum constant force ##F## to propel it through the water. Assume that the magnitude of the resistive drag force of the water experienced by the submarine is ##kv##, where ##k## is the drag coefficient and ##v## is the instantaneous speed of...

I am currently doing a research project in the attenuation of pressure waves. With an focus on dealing with sonic booms the are generated from high speed train tunnels. my experiments involved pressurizing a cylinder then using a rapid release valve allowing the air to escape along a pipe. I...

Homework Statement In a colliding beam apparatus, two beams of protons are aimed at each other. The first proton moves with a speed of 0.82c to the right; the second moves with a speed of 0.86c to the left. Both speeds are measured relative to the laboratory frame of reference. What is the...

Homework Statement A boat of mass 1000 kg is moving at 25 m/s. The friction force ##f## is proportional to the speed ##v## of the boat, ##f = 70v##. How many time will take for the boat to reduce its speed to 12.5 m/s? Homework Equations ##\vec{F_r} = m \vec{a_r}## The Attempt at a Solution...

Homework Statement In a proton linear accelerator, protons are accelerated to have a kinetic energy of 530 MeV. What is the speed of these protons? (The rest mass of a proton is 1.67 × 10-27 kg.) Homework Equations E0=m0c^2 E=E0/√1-(v^2)/(c^2) E = KE + E0 The Attempt at a Solution Recognize...

Hello! My question is: If you travel in a material at the same speed as the speed of light (I assumed this is possible due to the existence of Cherenkov radiation) you will see the light basically stationary so you see a constant electric field which means no magnetic field. But light has both...

Hello. I am working on planning to build a small pnumatic tricycle. I got far in my calculations, but not quite finished because I am stuck. If someone could check my math, that'd be great, but my problem starts at the second line. ______________________________________________ 1. Let's say...

The speed of light is constant, in what ever direction, that's not disputed. Now in relativity that as I understand light speed constant C is bound up with time, eg faster you go faster time pass for an outside observer but stays the same in your field of reference. Or to put it another way the...

Consider a circle rotating about a point X on its circumference at ##\omega = 2## rad/s. That means all points on and in the circle rotate at the same ##\omega = 2## rad/s. What are the angular velocities of various different points, say points A, B and C, with respect to the centre O of the...

Hi, I want to measure the motor resistance of a gear DC motor by experimentation and Ohm's Law. Should I measure the current without the gear head, with the gear head, stall current (with gear head) or stall current (without gear head)? I am trying to obtain values for Equation 4 in...

High school student here. I have just over a month until my AP Calculus exam. I love math and I'm confident that I understand all the concepts necessary to ace the exam. Here's the catch: Whenever I work with a ticking clock, I either don't finish every question in time or make a bunch of silly...

For example let's a satellite was orbiting the moon which has no atmosphere. If the moon suddenly started spinning twice as fast would it effect the satellite's orbit even though the satellite is separated by the vacuum of space from the moon? Easier way to put it, if the Earth suddenly spun...

I am currently studying Faraday's law and electromagnets and in class we were told that if you had a coil and say a bar magnet was passed through it the faster the magnetic field was applied to the coil the greater the induced voltage or emf would be. I do not understand why the speed would...

Could einstein's theory be completely wrong if we discovered that the speed of light is different in an another galaxy ( speed light isn't constant) and if we proven that there is particles or objects which moves faster than light by 100 or 1000 times?

Okay this has has been driving me crazy. I would like to know how a conveyor speed can be calculated on the basis of chain pitch, sprocket PCD & no. of teeth and output RPM of gearmotor. So here is a practical example I'm having to solve at the moment: I have to drive a conveyor at a speed of...

Homework Statement Why is the formula ##p = \frac{1}{3}\rho<c^2>## used to calculate the mean square speed at 273K? Why 273K?

Homework Statement The closest star system is about 4.3 light years away from Earth. A spacetug is able to move a cargo ship at a constant force of g=9.8N/kg times the mass of the cargo ship for many years. Starting from rest, speed up the cargo ship until you're halfway to the nearest stars...

Greetings, It's been quite a while since I had to do anything with velocity, friction, mass, and practically any physics over simple calculations. My car was hit yesterday while parked. There were no injuries, and it still drives just fine. The collision was hard enough to deploy the other...

Hi - I know that the information that I can provide here is too limited for a totally accurate answer, but is it possible to come up with a reasonable estimate? One vehicle, snow tires, on dry pavement, 6 degrees celsius, is motionless. Second vehicle strikes first in the rear. No evidence of...

Homework Statement Homework Equations ... The Attempt at a Solution I've been searching for the relation between the spinning speed and inertia in equation form. I do know that since the skater inertia is smaller the spinning speed is faster but that about it. Any hint would be helpful. One...

Homework Statement The problem is as follows; A boy begins to walk eastward along a street infront of his house and the graph of his displacement from the house is shown in the figure. His average speed for the whole time interval is equal to...

Hi guys, How would I go about calculating gear speed in rpm? If I know the input shaft speed, output shaft speed, gear ratios and tyre size. Thanks.

Hi! I am trying to find the time for an electron to accelerate in a uniform electric field from u1 to u2. In the textbook, I found that time is found by integrating d(u/(1-u^2/c^2)^(1/2))=(qE/m_0)⋅dt and they get u/(1-u^2/c^2)^(1/2) = qEt/m_0 by integrating from t=0 and u=0 to t=t and u=u I...

I have been pondering. Why is it that we use the rms speed in the equation Ek = 1/2 m vrms2, as opposed to just the mean speed2

Hi, Simple question. if a ship is getting close to the speed of light its momentum (mass) will continue to increase requiring more energy to propel faster. The fuel in the ship will also gain energy and mass as it accelerates. at C it will require infinite energy because it will have infinite...