Speed Definition and 999 Threads

Homework Statement Two particles in a high-energy accelerator experiment approach each other head-on with a relative speed of 0.890c. Both particles travel at the same speed as measured in the laboratory. What is the speed of each particle, as measured in the laboratory? Homework Equations...

Homework Statement A car initially traveling at 29.0 m/s undergoes a constant negative acceleration of magnitude 1.75 m/s2after its brakes are applied. (a) How many revolutions does each tire make before the car comes to a stop, assuming the car does not skid and the tires have radii of 0.330...

I'm studying history of electromagnetism. Here is my question regarding Maxwell's classical brilliant work. I understand these constants (for now) And I understand this: And I understand this: But I need to understand how this math below gets us to the speed of light. I don't understand...

Homework Statement Through what potential difference must an electron (starting from rest) be accelerated if it is to achieve a speed of 3.0 x 10^7 m/s? a . 5.8 kV b. 2.6 kV c. 7.1 kV d. 8.6 kV e. 5.1 kV Homework Equations me = 9.11 × 10−31 kg |qe| ≡ e = 1.6 × 10−19 C F = ma Eq = ma V = Eq/r...

Homework Statement 28. Particle A (mass = m, charge = Q) and B (mass = m, charge = 5 Q) are released from rest with the distance between them equal to 1.0 m. If Q = 12 μC, what is the kinetic energy of particle B at the instant when the particles are 3.0 m apart? a . 8.6 J b. 3.8 J c. 6.0...

I know that the speed of light is different in different mediums. The speed of light in Cesium as a medium is actually higher than the speed of light in vacuum. How is that possible? Shouldn't it be fastest in vacuum? [Mentors note: this post has been lightly edited as part of splitting it out...

I need to make an integral to fine the speed of the earth. Say the radius is 6378137 meters. How would I account for things closer to the axis that have a radius of 0.0001 meters? I don't think I can just take the speed at the radius. So I found that the Earth rotates at 6.963448857E-4 revs/min...

Trying to figure out how much air can (or would) flow through an air intake on a vehicle. I have a rectangular intake opening that is 13.52 square inches, the vehicle is traveling at 60 MPH for 1 hour. Obviously more air is being forced into the intake due to the speed but I can't sort out...

We all know that the state of matter can be changed by increasing temperature or by applying pressure. And, all of these, in some way lead to a change in the particles' speed. The speed of the particle decides the state of matter. So, if we were to throw an object at very high speeds, like 50%...

I'm a bit confused as to why the speed of light changes in an accelerating ship relative to an onboard observer. In other words, on a ship with a clock at the nose and a clock and observer at the tail, in an accelerating ship, the clock at the nose will tic faster. The reason (according to a...

I'm doing a fun home project, and it involves water flowing through a metal pipe, where the surrounding is significantly lower temperature than the water in the pipe. The point of the exercise is to cool the water in the pipe as it flows through it. The question is, what influence does flow...

Is anyone expermently measured two way speed of light from moving source using time of flight?

Hello, I have a physics question that I am hoping the forum can answer. I have lots of them actually, but I would like to start with the one question and go from there. Ideally the answer to the question should be based upon current accepted physics theory. The Question: How do objects...

Santa Fe is approximately 33.88 degrees north of the equator. Given that the Earth's radius at the equator is 3960 mi and the Earth spins around its axis completely in 24 hours, what is the linear speed of Santa Fe around the Earth's axis in mi/hr? I don't know where to start! Thank you so much!

Romer measured speed of light using moon's of Jupiter but he got value with a error of 26%. Is anyone did same experiment in modern era? And what value they got?

Homework Statement In the far future, humans have built a space elevator as a cheap means of access to space. However before that could be done, a few basic principles had to be worked out. . . a) What is the minimum initial speed (in an Earth-centered inertial reference frame) needed for an...

Scenario: You have two black holes approaching, one from the left (A), one from the right (B), each at speed S. They are offset vertically. S is sufficiently high that they will deflect passed each other without merging. Question: Suppose the speed S is high enough so that the event...

Homework Statement In a convoy on a long straight level road, 50 identical cars are at rest in a queue at equal separation ## 10 m ## from each other. Engine of a car can provide a constant acceleration of ##2 m/s^2##. And brakes can provide a maximum deceleration of ##4m/s^2##. When an order...

Hi, Pressure vessels have caps on top of them. These caps are secured with tri clamps and if you need to remove them you have to make sure that the tank's pressure is released. If the tank is under pressure (say 10psi) and an operator removes the cap (A is known), what is the speed of the cap?

Hi, I need help with this problem: Homework Statement Condition: an object has to move from point A to point B in the least time possible. The distance between the points is L. The object can accelerate (decelerate) with a fixed acceleration ##a## or move with a constant speed. What maximum...

1. The question... "Blood is a conducting fluid. When flowing through an artery of diameter 10mm which is subject to a constant magnetic field of strength 60mT, an e.m.f. of 0.3mV appears across the width of the artery. Calculate the speed of the blood" 3. The solution... The solution given...

Question: Beginning at rest from the top of the slope, what is the speed at C and at D? I don’t understand how to solve this question without being given the skier’s mass, acceleration, time or angle. I drew a triangle vector diagram with delta d1 using the distances given. And i made gravity...

Homework Statement The acceleration of a particle given a=A√t where A=2.0 m/s5/2. At t=0, v=7.5 m/s and x=0. (a) What is the speed as a function of time? (b) What is the displacement as a function of time? (c) What are the acceleration, speed, and displacement at t=5.0s. Homework EquationsThe...

Hi all. I have a question about something Nima Arkani-Hamed said in his lecture on space-time about space contraction near light speed. I included a link to the lecture at the point where he refers to contraction of two space ships with a 'cable' between them, they are accelerating towards the...

Homework Statement A point moves rectilinearly in one direction. The figure shows the distance s traveled by the point as a function of time. Using the graph, find: The average speed of the point during the movement time. Maximum speed The moment t0 in which the instantaneous speed is equal to...

Hello there, I'm new here and i need some help on my home work. A DVD drive rotates at an angular frequency of 4800 rpm. a) what is it's angular speed in rpm? b) at 4800 rpm, what is the linear speed (in knm/hr) of (i) the center point and points (ii) 5 cm and (iii) 6 cm from the center? Thanks!

It is commonly said that the speed of light when traveling inside materials is lower than that of light in vacuum, but I don't understand how this can be true. It is the same light traveling, so how can it act differently? Does light appear to be slower in materials because it is not following a...

Homework Statement What is the ideal speed to take a 70 m radius curve banked at a 30.0° angle? Homework Equations tan θ = v2/r g The Attempt at a Solution This has me stuck, when I attempted this I came to the equation v= √ g*r* tan Θ But when I substitute in the variables, I enter then into...

The answer is 3.079*10^-26 kg I tried doing E=mc^2 20*10^9*1.602*10^-19=m*(3*10^8)^2 m=3.56*10^-26 kg However when I do E=γmc^2 I get the correct answer. Is the question wrong, because isn't it 20 GeV of kinetic energy, not total energy?

Play from 3:00 It states that we will age slower if we were traveling at the speed of light compared to being on Earth. Would we not age the same but just be further away hypothetically? Next it states that if we travel away from a clock at the speed of light at 12:00, we would always see...

The problem is asking me to find the final speed of a 1100 kg car traveling at 24 m/s through 18m of mud, where the resistive force on the car is 17000 N. I don't actually know how to go about doing this, so any pointers in the right direction would be super helpful.

Hi All, Can somebody tell me what's the speed of the Graviton? As for Cherenkov Radiation, does exist a similar effect for Graviton? Thanks

Hi, The speed of light is given c=1/√(ε0μ0) where ε0 is permittivity of vacuum and μ0 is vacuum permeability. The permittivity and permeability of a material is given as ε=εrε0 and μ=μr)μ0 respectively where ε is absolute permittivity of the material and εr is relative permittivity of the...

Hello, this is my first forum question, so i hope it's at the right place. My question is about electrons, i know in a QM view electrons don't have a well defined position or speed. However i am curious, in a classic view of the electron would electrons closer to the nucleus move faster then...

I can find public information about the speed of the moon at max and min distance from the Earth (Ap vs Per) but how do I find the same information for the Earth's velocity around the same barycentre? The Earth's orbit around the barycentre is it a perfect circle or is it an ellipse? If it's an...

My question is about the speed of light. Our current understanding of light says that light is constant for all observers, and uses time dilation to explain this. Have we proven this? The speed of light emitted from a stationary object is equal to C. The speed of light emitted from a moving...

Hi, there is no particular question that I need help on, just something my lecturer told us in lesson which I couldn't quite understand so i'd like to check my understanding on this. I know that the speed of a soundwave is 'c' in undisturbed flow. Suppose the flow velocity is 'U'. If the...

How to find the angular speed, on which a spinning hollow cylindrical body breaks due to inertial stress(force)? I found 2 sources(http://www.roymech.co.uk/Useful_Tables/Cams_Springs/Flywheels.html (last 2 equations) ...

Homework Statement Both m1 and m2 (m1=2m2) masses can slide without friction over parallel and rigid bars that are placed at a distance d from each other. A spring with elastic constant k and with zero natural length connects both masses. The system is placed on a table. The system is released...

Homework Statement A uniform rod (mass = 1.5 kg) is 2.0 m long. The rod is pivoted about a horizontal, frictionless pin through one end. The rod is released from rest in a horizontal position. What is the angular speed of the rod when the rod makes an angle of 30 degrees with the horizontal...

Homework Statement This isn't really a homework but a project I'm doing that's due soon. In our multivariable calculus class, we're creating a 3D roller coaster, and I need to explain the physics behind the roller coasters. For a roller coaster loop, if it were perfectly circular, we would...

Homework Statement https://imgur.com/a/OLPyMfK Homework Equations F=ma W=F*d W=T2 - T1The Attempt at a Solution For part A i figured it must be E because that is the only one that goes to 0 as the hit says. but nothing about this problem makes any sense to me. Where it says "You notice...

I am trying to find the thermal speed of electron at room temperature. kT = (1/2)mv^2 which gives v=√((2kT)/m) but answer says it should be √((kT)/m) Where did that 2 go?

Homework Statement Homework Equations v = s/t a = v/t The Attempt at a Solution My thinking was that through this small distance of air since velocity would increase due to the change in position changing at an increasing rate and thus since velocity is increasing then obviously...

I know that special relativity is based on the postulate that an object that travels at the speed of light with respect to one inertial observer must travel with the speed of light with respect to all inertial observers. This postulate implies that no two inertial frames can differ by a relative...

Homework Statement *I cannot place the original image due to copyright reasons, but the image above is a good alternative. "Wave crests spread out behind a boat as shown above. What do the wave crests indicate about the boat's speed?" It is increasing. It is less than the speed of the water...

hello, i am a near light runner at 3000000 km from us there is a mirror to start the run , my friend turns on a very powerful lamp and i start running toward the mirror me and my friend will see both the light coming back after 20 seconds?

Is the average nonlocal speed of light the same for travel out from the Sun and travel back to the Sun over the distances the Voyagers are now located?

Homework Statement You throw baseballs at a mass rate of σ kg/s (assume a continuous rate) with speed u at the back of a car. They collide elastically with the car. The car starts at rest and has mass M. It moves on the ground with no friction. Find its speed and position as a function of time...

Homework Statement Consider a central force is attractive but which passes through the force center. In other words, consider an orbit of radius a which is centered at (a,0), with the force center at the origin c.) Suppose the speed at the apogee is v0 Find the oribital speed v as a function of...