Relative Definition and 1000 Threads

Homework Statement why we need to consider 2 moment caused by the 85Nm in this question ? The question ask for the determine the angle of twist of gear A relative to D . Homework EquationsThe Attempt at a Solution Why shouldn't the angle of twist = (85)(0.4) / ( (0.5pi)( 0.015^4-...

Raoult's law: P = xP* , combined with Dalton's law becomes y = xP*/P Henry's law: P = kx, combined with Dalton's law becomes y = kx/P Relative volatility: y = ax/(1 + (a -1)x) Raoult's law and Henry's law are linear when temperature and pressure are kept constant. But if we vary the temperature...

Homework Statement Inside a NASA test vehicle, a 3.50-kg ball is pulled along by a horizontal ideal spring fixed to a friction-free table. The force constant of the spring is 226 N/m . The vehicle has a steady acceleration of 5.00 m/s2, and the ball is not oscillating. Suddenly, when the...

We have 3 clocks A, B and C. They are in a straight line (Time 1). Clock A rotates around it's axis and clocks B and C rotates around clock A at distance L1 and L2 respectively. Distance L2 > L1. Clocks B and C rotates around clock A so they stay in straight line. Clock A rotates around it's...

Homework Statement not sure fully sure on this equation Homework Equations f=fo√(1±v/c)/(1±v/c)[/B]The Attempt at a Solution is it just the relationship between the observed frequency and the proper frequency or something? [/B]

My university's professors have a pathological obsession with non inertial frames of reference which apparently has been going on for decades. As a result we work tons of these problems involving kinematics, dynamics and so on. However, none of the books listed in the bibliography of the course...

Consider the case in which an incoming particle collides with stationary target particle producing new particles through the interaction. For example, $$e^{-}+e^{+}\rightarrow X+\bar{X}$$ My question is, why in general do the particles produced in such an interaction propagate outwards are...

Homework Statement When a cart travel to the left at v=-10m/s, the angle of rain come towards it is 50o from normal. When the cart travel to the right at v=10m/s, the angle of rain water come is perpendicular to it. What is the angle of rain come to the earth? Homework Equations relative...

Homework Statement On a long bus ride, you walk from your seat to the back of the bus to use the restroom. The bus is driving at 120 km/h , and you walk at 2.5 m/s from your seat to the restroom. How quickly are you moving relative to the ground? Homework Equations vpg=vpb+vbg The Attempt at a...

Homework Statement In the mechanism shown below, the angular velocity of link 2 is 17 rad/s CW, constant. Find the angular velocity (magnitude and direction) of link 3. The distance between A and C is 109 mm, the length of link 3 is 125 mm, and θ= 111°. Note: B is a pin-slider In the...

Given that the time is relatively slower for a moving object that a stationary object, does the relative difference have an effect on satellite communications? For instance, if a geostationary satellite, which is traveling very fast to appear stationary on Earth (and therefore experiencing a...

Two trains having lengths of 120 m and 100 m are running in the opposite directions with velocities 40 km/h and 50 km/h . In what time they will completely cross each other? In the solution it's given that Time taken by the two trains to cross each other = sum of length of trains/relative speed...

Homework Statement A person on a train watches a car approaching a railway crossing ahead on his track. It appears that the car’s driver has fallen asleep and will not slow down. The train is traveling north‐east at 100km/h while the car is going west at 80km/h. The train is 4 km and the car is...

Homework Statement A particle of mass ##m## rotates about ##Z-##axis in a circle of radius ##a## with a uniform angular speed ##\omega##. It is viewed from a frame rotating about the ##Z-##axis with a uniform angular speed ##\omega_0##. Find the centrifugal force on the particle. Homework...

Homework Statement Homework Equations [/B] Va = Va/c + Vc Va = 0.2 + Vc Vb = Vd The Attempt at a Solution I began by finding the instant centre of rotations of AB and CD. Both of these form a right angle triangle and the length of A -> ICab = 200mm and C -> ICcd = 300mm Va/0.2 * 0.15 = Vb...

Homework Statement A farmer is throwing bales of hay off the back of his tractor with a speed of 3 m/s relative to the tractor, which is moving west with a speed of 7 m/s. Determine the speed and direction of hay bales relative to the ground. Homework Equations subtract the speeds, since they...

Homework Statement Homework Statement A newspaper boy throws papers sideways onto the porches of his customers while riding his bicycle along the sidewalk. The sidewalk is 15m in front of the porches. The boy throws the papers at a horizontal speed of 6m/s relative to himself, and rides the...

Homework Statement Two ships A and B are 4 km apart. A is due west of B. If A moves with uniform velocity of 8 km/hr due east and B moves with a uniform velocity of 6 km/hr due south. Calculate 1) the magnitudeof the velocity of A in relation to B 2) the closest distance apart of A and B...

Homework Statement After flying for 15 min in a wind blowing 42 km/h at an angle of 31° south of east, an airplane pilot is over a town that is 50 km due north of the starting point. What is the speed of the airplane relative to the air? Homework Equations Vx of wind=42km/hr*cos(31) Vy of...

Homework Statement A helicopter is flying in a straight line over a level field at a constant speed of 6.8 m/s and at a constant altitude of 9.4 m. A package is ejected horizontally from the helicopter with an initial velocity of 12.0 m/s relative to the helicopter, and in a direction opposite...

As I understand relativity, length gets contracted when speed raises. Does that imply that the maps we make of the universe actually describes the universe seen from our perspective, and that these maps would have looked different in size for an observer moving at different speed??

Everyone "knows" that \lim_{x\rightarrow ∞}\frac{2^x}{x^2} = ∞. We "know" this because 2x grows faster than x2. I use quotes because this is just what we're told in basic calculus classes. But what about a theorem for this? I've searched through google, looked through various university homework...

Homework Statement An event occurs in S at x = 6 x 10^8 meters and S' at x' = 6 x 10^8 meters. Find the relative velocity of the systems. Assume that S refers to an inertial system (x,y,z,t), and S' refers to an inertial system (x',y',z',t') moving along +x axis with speed v relative to S. The...

Homework Statement Homework Equations Work = - (integral of) (E dot dl) The Attempt at a Solution Hi, I know that the right answer is D zero, but I fail to understand why. I said that the answer was A as I have different charges, and I thought that depending on how I approach each...

Homework Statement Homework Equations a= omega^2*r The Attempt at a Solution a_A/B = a_A - a_B a_A = 10^2*r (-î) a_B = 10^2*r (+ĵ) a_A/B = 10^2*r (-î) - 10^2*r (+ĵ) => -200 î -200 ĵ why is the answer 200 î -200 ĵ (accelerate in +î direction) ?

Homework Statement Homework Equations v_theta = r * theta_dot 1 knot = 1852 m The Attempt at a Solution v_0 = 6 * (1852m/h) * (1/3600 h/s) = 3.087 m/s

Homework Statement A distance R is measured to be 3.400±0.003m. What is the relative uncertainty in R? 9×10-4 What is the relative uncertainty in R^-2? Homework EquationsThe Attempt at a Solution Relative uncertainty of R is 0.003/3.4=8.8e-4 Relative uncertainty of R^-2= -2(8.8e-4)=-1.76e-3...

Homework Statement A ship sets sail from Rotterdam, The Netherlands, heading due north at 7.00 m/s relative to the water. The local ocean current is 1.50 m/s in a direction 40.0º north of east. What is the velocity of the ship relative to the Earth? Homework Equations Vr=Vs-Vc r=relative...

<Moderator note: moved from technical forums, so no template> Problem: Two trains (A and B) are moving along parallel tracks at different speeds. A person sitting on train A looks out the window and sees two things happen: a firecracker explodes right outside his window, and, exactly 1.0...

Ok so I have this problem which I wasn't really sure how to approach; when I looked at the results I understood that it needed Newton's 3rd law to be solved and I sort of made it up, but I don't understand why it turns out to be correct(i only have the results, no explanation) and I feel like...

Not sure whether this is an intro physics or intro calculus/related rates problem. 1. Homework Statement Suppose a point P lies at (x,y)=(0,1) meters. A car is traveling at 30 meters/second along the x-axis towards +∞. Define r to be the distance between P and the car at any time t. I...

Back story : I have cheap 12v LED 5050 strip from China. Question: how do LEDs respond to 13v and 14v in terms of % intensity with higher voltage neglecting lifespan and assuming proper heat dissipation. Details: the LEDs at 60/m rated 14.6w at 12v. They are typically 3led in series with a...

I have a question regarding time dilation due to relative velocity. (It's just about time dilation due to velocity not about gravitational effects.) I have seen a theory where time dilation is not relative, but always considered against an absolute frame of reference. The absolute frame of...

Homework Statement A train is traveling east along a straight run of track at 72.0 km/hr. Inside, two siblings 1.9 m apart are playing catch directly across the aisle. The kid wearing a P.J.Harvey T-shirt throws the ball horizontally north. The ball crosses the train and is caught 0.75 s later...

Many textbooks and online sources give the relative permittivity of water as about 80 and the refractive index as 1.33. If you use the definition of refractive index to find the speed of light in water, you will find v = c/n ~ 2.56e8 m/s. However, if you use the equation to find the speed of...

I am drowning in math right now and would love some help bc I am horrible at math. Here is what I have got. Question: 1. The four major blood groups are designated A, B, AB and O. Within each group there are two types; positive and negative. Find data on the relative frequency of these eight...

Two vehicles leave simultaneously from a fork in a road. Vehicle A travels at a velocity of 85 km/h north-east. Vehicle B travels at 104 km/h directly east. Calculate the velocity of vehicle A relative to the velocity of vehicle B. Answer (from memorandum): http://imgur.com/a/L0prH I do not...

Homework Statement I'm trying to find da/a to calculate the relative possible error in the radial acceleration. The equation I have to derive from is a = 4π²n²rt ⁻² (it cannot be a = v²/r). I'm not really sure how to find da since it has 3 variables? Homework Equations a = 4π²n²rt ⁻² da/a =...

I would like to be sure about one case of the use of Doppler effect with sound waves. If the medium (in the case of sound air) is moving, but there is no relative motion between the observer and the source there is no Doppler effect at all. (And the absence of relative motion is...

Does a magnet have to penetrate the plane of a coil in order to generate an emf in the coil? Would an emf be obtained if the coil only passes through the magnetic lines of force, without the magnet crossing the plane of the coil? Thank you.

What is the cause of hyperfine line splitting? I saw somewhere that it was because of spin quantum number and somewhere else that it was because of how electrons interact in the atom. And relative intensity of spectral lines? I'd assume it's due to the probability of electron jumps being more...

Homework Statement A stationary person observes that rain is falling vertically down at 30km/hr. A cyclist is moving on the level road, at 10km/hr. In which direction the cyclist should hold his umbrella to prevent himself from the rain? 2. The attempt at a solution I used triangle law to...

Hi there. I want to compare the mean lifetimes of two particles which decay in a way given by two known reaction formulas, such as ##\rho^0 \rightarrow \pi^+ + \pi^-## and ##\Xi^- \rightarrow \Lambda^0 + \pi^-## In this case it's easy: since the first one corresponds to a first interaction...

Homework Statement A person decides to swim across a river 84m wide that has a current moving with a velocity of 0.40m/s[E]. The person swims 0.70m/s[N] relative to the water. In what direction should she swim if she lands at a point directly north of her starting position? Note: This is part...

In Galilean Relativity, laws of mechanics are invariant across frames. In all the frames they are the same. So, in Dynamics and Relativity by W.D.McComb, it is written that this implies you cannot perform any experiment in an inertial frame that can tell whether an inertial frame is moving or...

f(x)=x^3-12x^2+15x+16 Use the first derivative to find relative maximums, minimums, or neither. I am trying to find x to plug it back into f(x) to get my y value, but I am not sure if I am getting the correct x value. I did the first derivative and got 3x^2-24x+15. I then set it equal to 0 and...

Reading the Wikipedia article makes my head spin! Somehow the figure https://en.m.wikipedia.org/wiki/File:Observable_universe_logarithmic_illustration.png doesn't seem quite right. I don't understand how the CMBR doesn't define the edge of the universe. If we can see the CMBR that happened near...

Among the following compounds I think D compound has more rate of solvolysis in 50% aq.ethanol at 45°C than compound C . Due to more resonance. But the compound C has more rate . Why?

Hey all, As environmental physics isn't my forte, I have a problem that has been annoying me for about a month now at work and I am still getting no where with it... so any help with this head ache is much appreciated. The problem at hand is as follows. A sealed metal housing is purged with...

From the observation point of Earth, you can say that the sky "moves" while the Earth is still. From this point, an observer on Earth would see a distant galaxy travel a circumference millions of light years lomg around the Earth in only a day - resulting in a velocity faster than light. Special...