Relative Definition and 1000 Threads

Homework Statement A geiger counter measures 750 counts in 5 min a) determine the average counting rate and the standard deviation of the counting rate. b) find the relative error c) How long would you want to count to get a relative error of 1%? Homework Equations standard...

The three main effects of SR occur in inertial frames and change the description of space-time relative to a particular observer. My question here is how do these effects occur on Earth, since we know that motion on Earth is non-inertial. I know that we travel at small speeds and that we can't...

To calculate the detected frequency from the source frequency, we use this formula: { f }_{ D }=\frac { v\pm { v }_{ D } }{ v\pm { v }_{ s } } { f }_{ s } where {v}_{s}, {v}_{D} are velocities of the source and the detector respectively with reference to the medium. My question is why do...

Homework Statement A rower's maximum speed in still water is 6.0 ft/s. He decides to cross a 60 ft. wide river (at his maximum speed), with an apparent heading of 30° north of east. The river's current (relative to the ground) is flowing south at a speed of 1.0 ft/s. Find the rower's speed and...

Hi all! Let me use an example to make this clear. There is a car traveling directly toward a man at 10m/s. The car is pressing down its horn, producing a frequency of 100hz. The speed of sound is 330 m/s. What frequency does the man hear? Ok, so we can use the equation: f_observer=(...

Homework Statement http://puu.sh/7vC46.png http://puu.sh/7vBG5.png Note: In this image the ohm symbol represents the angular frequency of the Earth's rotation Homework Equations Gamma = 1/SQRT(1-v^2/c^2) V (relative to centre of earth) = angular frequency(R+h) +/- v v= plane velocity...

Homework Statement The muon is an unstable elementary particle that decays via a weak-force interaction process into an electron and two neutrinos. The life time of muons in their rest frame is 2:197 s  2:197106 s. Nuclear reactions in the upper atmosphere, precipitated by the impact of...

Homework Statement A block of copper at 100.0° C comes into contact with a block of aluminum at 20.0°C. The final temperature of the blocks is 60.0°C. What are the relative masses of the blocks? Homework Equations mcΔT copper specific heat = .386 J/g°C aluminum specific heat = .900...

Homework Statement An airplane pilot sets a compass course due west and maintains an airspeed of 225km/h . After flying for a time of 0.470h , she finds herself over a town a distance 119km west and a distance 14km south of her starting point. 1) Find the magnitude of the wind velocity...

Homework Statement find the derivation of χm=μr-1 where Xm is the magnetic susceptibility and μ is the relative permeability. Homework Equations M=Xm.H M is the magnetization,H is the magnetic field μr=μ/μo where μo is the permeability of a vacuum, The Attempt at a Solution I...

Earth has a huge angular velocity regarding its rotation. Now let's imagine that the Earth has the velocity of 400 km/s relative to some inertial frame. What will be the velocity of Earth when we take the rotation into account combined with inertial motion? How do the 2 combine? Thanks in...

I'm not sure if this is the right place to post- sorry if it's not. ********* Does anyone have an image or link to a website that shows the relative strengths of the strong, weak and electromagnetic forces as a function of energy? I like it as a way to explain spontaneous symmetry breaking...

Hello, If I have a measurement of 1cm, and have an absolute error of 0.1 cm, I know that I can write my measurement as (1±0.1)cm. If I want to write it with its relative error instead of an absolute error, can I still use the bracket? i.e) (1±10%)cm ? Thank you!

When we study the bound state of quarks, i.e. mesons, the relative momentum is given as; q=1/2(p1-p2). Where p1 and 2, are momentum of quark and anti-quark, respectively.My question is, what is the value of q at center of mass frame? For example, P=(0,iM), at center of mass frame, where P is...

Okay here goes! A boat "A" travels due north at a velocity of 18km/h , and a boat "B" travels south-east at 15km/h. a) Calculate the velocity of "A" relative to "B". b) If "B" is initially 30km north of "A", calculate the shortest distance between the two boats during the motion. Right, so I...

Hey! :rolleyes: I have also an other question :o Suppose the base $\beta =10$ ,the precision $t=3$, $-L=U=10$ and $$A=(317+0.3)-(171.499+145.501)$$ I have to find the relative error for $A$. We don't make rounding.For example,if we have the value $345.924$ it is equal to $0.345924*10^3$ and the...

Homework Statement An airplane flies with a velocity of 55.0 m/s [ 35o N of W] with respect to the air (this is known as air speed). If the velocity of the airplane according to an observer on the ground is 40.0 m/s [53o N of W], what was the wind velocity? Homework Equations...

Homework Statement We have a saturated vapor mixture with relative humidity 80% at a termpature of 30 C. Find the specific enthalpy of the mixture. Homework Equations The Attempt at a Solution I missed a lecture and a session due to illness and have fallen behind. We are allowed...

Hello! :) I am looking at the following exercise: Let the linear system $Ax=b$ with $\begin{pmatrix} 2.001 & 2\\ 2& 2 \end{pmatrix}$ ,$b=\begin{bmatrix} 2.001 &2 \end{bmatrix}^T$ and y an approximate solution,so that $Ay-b=\begin{bmatrix} 0.001 &0 \end{bmatrix}^T$ .Find an upper bound of the...

The question is to rank the inertial forces, euler,coriolis and centrifugal in increasing order of strength, for a observer in the Earth' rotating frame, observing a body stationary in the UK. My thoughts are that coriolis = 2mw X (dr/dt), and so depends on the velocity so can only come into...

Homework Statement A motorboat is observed to travel 10 km/hr relative to Earth in the direction 37° north of east. If the velocity of the boat due to wind ONLY is 2 km/hr westward and that due to current is 4 km/hr southward, what is the magnitude and velocity of the motorboat due to its own...

Well, relativity says whatever moves, it's volume shrinks and mass increases (as observed). So if i am traveling at 99% c with respect to a massive neutron star, do that star become a black hole for me?

Homework Statement Indicator HIN is yellow at pH 1.0 or less, green at pH 2.0, and blue at pH 3.0 or above. A 0.004 M sample of colorless acid HA is treated. It develops a green-blue color halfway between pure green and pure blue. How do the strengths of HA and HIN compare? Homework...

Homework Statement Consider the bond dissociation enthalpy data: C-C, C≡C; N-N, N≡N. Bond dissociation enthalpies are, respectively: 348 kJ/mol, 812 kJ/mol, 163 kJ/mol, and 945 kJ/mol. Explain the data with regard to simple electronegativity considerations, which would lead one to...

If we could set the strong force to be ten times weaker (compared with the electromagnetic force) how much would the radius of the proton change if any? In the limit that the strength of the strong force goes to zero does the proton radius approach some limit? Thanks for any help!

I've been doing basic physics and i understand that to describe the Kinematics or trajectory/movement of things, we use the relationship between position, displacement, velocity, acceleration, and time while to describe the Dynamics or cause of motion, we use the relationship between...

I have to design a system to increase the relative humidity in a bunker. I would like to use a spray nozzle and service water. How could I determine how much the relative humidity would raiser per volume of water sprayed into the bunker. Known: - Volume of Bunker - Temperature - Initial...

Homework Statement Show that the two-body hamiltonianH_{\text{sys}}=\frac{\mathbf{p}_1^2}{2m_1}+\frac{\mathbf{p}_2^2}{2m_2}+V( \mathbf{r}_1,\mathbf{r}_2)can be separated into centre of mass and relative...

Is everything we know relative or is there something absolute in this universe?

I am really confused about relative velocity when one frame is rotating. Is it possible to have velocity/acceleration of A relative to B and velocity/acceleration of B relative to A not having same magnitude and opposite direction? Any explanation will be helpful! Thank you

Homework Statement On the Earth the Sun appears to rise and set about 365 times in one year. During the same 365 days, how many times does the Earth rotate on its axis relative to a distant star (a star beyond the Sun and out of our solar system)? Homework Equations The Attempt...

Homework Statement Two trains start from rest from two stations 5.0 km apart and travel, on two parallel railroad tracks, in opposite directions. One train accelerates uniformly at 2.5 m/s^2 and the other has a constant acceleration of 4.0 m/s^2. How far from the first station will they...

Homework Statement Photon with ##\lambda =10^{-12} m## hits an electron (Compton scattering). After the interaction the photon and electron move under relative angle of 90°. Calculate the kinetic energy of electron. Hint: First find the relation between ##\theta ## and ##\varphi##. (##\theta...

An 80 kg astronaut has become detached from the safety line connecting her to the International Space Station. She's 200m from the station, at rest relative to it, and has 4 min of air remaining. To get herself back, she tosses a 10 kg tool kit away from the station at 8 m/s. Will she make it...

Homework Statement A motorcyclist accelerates rapidly so the bike entirely rests on the back wheel, while the midpoint of the back wheel O' accelerates with constant acceleration a_o' horizontally. The entire bike rotatoes with angular velocity \frac{d}{dt} \theta and angular acceleration...

A boat is traveling upstream at 14 km/h with respect to a river that is flowing at 6 km/h (with respect to the ground). A man runs directly across the boat, from one side to the other, at 6 km/h (with respect to the boat). The speed of the man to the ground is ____? Attempt: vPG = vPB +...

Homework Statement A uranium atom (U), traveling with a velocity of 5.00 x 10^5 m/s relative to the containing tube breaks up into krypton (Kr) and barium (Ba). The krypton atom is ejected directly backwards at a velocity of 2.35 x 10^6 m/s relative to the barium after separation. With what...

If you had to give a physical reason for relative time, what would it be? (I will not be giving my view; just looking for yours.)

Homework Statement An object is moving in x-axis with given force Fx = -mω^{2}x, where ω is a positive constant. when t = 0 the object starts moving from point x_{0} > 0. a. Find the object's velocity function relative to x (v(x)) b. Find the object's position function relative to t (x(t))...

Hello, I have two vectors, the angle between them is dynamic and constantly changing. I have found a way to calculate the angle between these two vectors. But this angle is always a positive number even if i am looking left or right. How can i get context(wether vector DC,DB,DE,DF according to...

Hello forum members, I am trying to wrap my head around the concept of relative permittivity. I have read the Wikipedia article on the subject, but I don't feel quite satisfied. As far as I understand it, RP is essentially a measure of how well a given material holds a static charge relative to...

Given in my book- 1."Velocity Of approach - It is the rate at which distance between two moving particle decreases. V(Approach) =V1cosα + V2cosβ " 2."When the distance between two particles is minimum, the relative veloctiy of approcah is 0" 3."V1cosα + V2cosβ = 0 ...when distance is...

Homework Statement The escalator that leads down into a subway station has a length of 30.0 meters and a speed of 1.8 meters/second. relative to the ground. A student is coming out of the station by running in the wrong direction on this escalator. The local record time for this trick is 11...

Homework Statement I have attached a picture of the diagram of the problem. I am supposed to determine the angular velocities of links OB and BA if the velocity of the slider at the instant shown is 7.5 m/s to the left. Homework Equations Va = Vb + Vab (Velocity of A is equal to the...

Homework Statement An airplane flies at an altitude of 8 miles toward a point directly over an observer (see figure). The speed of the plane is 600 miles per hour. Find the rates at which the angle of elevation θ is changing when the angle is θ = 30°, θ = 60°, and θ = 80°. The Attempt...

Homework Statement You are at the mall on the top step of a down escalator when you lean over laterally to see your 1.80 m tall physics professor on the bottom step of the adjacent up escalator. Unfortunately, the ice cream you hold in your hand falls out of its cone as you lean. The two...

Hello everyone, One of the conclusions of relativity is that no massive object can move at v ≥ c, but with respect to what, I don't understand? Let me try making my question clearer with an example: Suppose there are two bodies both moving side by side at v=0.9c relative to earth. The relative...

Homework Statement An airplane has a velocity 325km/h relative to the air. It is going in a direction [S30W]. There is a wind velocity of 80km/h[W]. What is the velocity of the plane relative to the ground? Homework Equations aVg + pVa = pVg (velocity of air relative to ground +...

I just woke up from a nightmare that terrified me to my core. I had recently seen this video from Sixty Symbols regarding the apparent paradox of time dilatation http://goo.gl/dwOvg1 on a train moving near the speed of light heading towards a tunnel with guillotines at each end. The...

Hello all, Would appreciate some guidance here. I have an air compressor compressing ambient air to 3000 psi into a 425cu-in tank. I have the volumetric flow rate at the exit. If I was looking for relative humidity, dew point, and moisture content/accumulation at the exit, how would I go...