Relative Definition and 1000 Threads

Homework Statement A balloon with person A in it has a force of gravity of 3000N acting on it. The balloon has an upward force of 3800N due to the hot air in it. Two people are keeping the balloon hovering just above their heads by holding onto ropes attached to each side of the balloon. If...

Homework Statement Bar OA has a counterclockwise angular velocity ω0 = 1.8 rad/s. Rod BC slides freely through the pivoted collar attached to OA. Determine the angular velocity ωBC of rod BC (positive if counterclockwise, negative if clockwise) and the velocity vrel of collar A relative to...

This is a prediction that is made every day. If I do a back test assemble a curve composed of each days' prediction, I get fair results. However, if I smooth this backtest curve, I get fantastic results. So what I need to do is take today's prediction and the prediction time history...

Gravitational effects from large bodies of mass are nonexistent. These golden retrievers are in deep, deep space. They are named Mr. Squabbles, Alfredo, and Billy. Mr. Squabbles is suspended in space (at rest)--he has not been acted upon by any force. (If that's possible.) Alfredo has a...

Is how we choose to describe relative velocity arbitrary? For example, say I am floating in space with only Ball A and Ball B for reference. Ball A is moving away from me at 10mph, and Ball B at 20mph. I could say that I am stationary, and Ball A and Ball B are traveling at 10 and 20mph...

Source: Engineering Mechanics Dynamics - Hibbeler ---------------------- My friends and I have discussed and have no idea how to solve. So we looked at the textbook. We were told to use this equation. In this equation, A/B means 'A respect to B' Also, the equation is derived based on an...

Hello, If a man how is able to row on still water at 2.5m/s. If the water is moving at 1.5m/s, in which direction should he row. The answer is he should row at 53.1 degrees upstream but the question for an observer on the boat and another observer on land, how will the motion appear? For an...

Homework Statement https://dl.dropbox.com/u/51681259/physics_diag.png Object C & P are moving at the same constant velocity to the right, in the configuration of the image. The friction between object C and the ground is 0. Suddenly the friction increases to μ=0.9 between the ground and...

relative velocity of light in special theory of realtivity?? hello everyone.. as per the theory of special relativity, Postulate2:Any ray of light moves in the 'stationary' system of co-ordinates with the determined velocity c, whether the ray be emitted by a stationary or by a moving body...

Homework Statement If the truck was not stationary but was moving horizontally towards the ball at 25 ms-1, what would be the speed of the ball, relative to the ground, after the collision (in ms-1)? Mass of ball = 0.2 kg Mass of truck = 20 tonnes Initial velocity of ball = 20 ms-1 (to the...

Homework Statement A river flows with a velocity of 3 m/s east. The river is 300 m wide. A boat is moving 10 m/s due north. If the river flow is not corrected for, how far will the boat have moved downstream by the time is reaches the far shore? Homework Equations Trigonometry and...

Homework Statement The ends of the slender bar remain in contact with their respective support surfaces. If end has a velocity in the direction shown, determine the angular velocity of the bar and the velocity of end. Answers: ω=1.394 rad/s VA=0.408 m/s down Homework Equations Va=Vb +Va/b...

when people say you can travel into the future by traveling close to the speed of light, does that mean relative to the earth? So technically, we are moving close to the speed of light relative to a distant object in the universe going that speed?

Homework Statement An aircraft flew due east fro P to Q at u1 km/h.Wind speed from south west was v km/h.On the return journey from Q to P,due west, the aircraft's speed was u2 km/h, the wind velocity being unchanged.If the speed of the aircraft in still air was x km/h, x>v,show by resolving...

Lets say I have a moving object that has speed v_1 and mass m_1 and it collides with a more massive object of mass m_2 And this mass is at rest and when they collide they stick together. If I use momentum conservation I would get m_1 v_1=(m_1+m_2)(v_2) and v_2 is the speed...

Hi, I'm trying to adapt the doppler shift formula for a stationary listener and a source traveling in a straight line towards/away from the listener to the case where the source does not move straight towards the listener. For example, suppose that I am looking north and train further in the...

Homework Statement A boat crosses river, 240 m wide,which flows parallel to the straight banks with velocity v1 = 12i, while the velocity of the boat relative to the river is v2 = 5j where v1 and v2 are measure in m/s (i) find the magnitude of the actual velocity of the boat. (ii) find...

Hi everyone. I rediscovered a question I caught in High-school that I never encountered a answer to. Given a spaceship going back and forth into space, during it's travel it accelerate close to c relative to earth. At an appropriate distance it breaks and returns in a similar fashion. My...

Mass curves spacetime. The relative acceleration of nearby geodesics of free test particles indicates the sign of the spacetime curvature. Convergent geodesics mean positive, divergent negative curvature. But also the metric expansion of space curves spacetime. The geodesics may be convergent...

Hello, all. I'm trying to wrap my mind around relativity, and I just wanted to make sure I'm not getting it wrong. I'd really appreciate it if anyone were to take the time to chime in on this hypothetical that I think explains it. Say someone was to put two lasers (in a "gravity free"...

Homework Statement An elevator is moving upward at a constant speed of 2.50 m/s. A bolt in the elevator ceiling 3.00m above the elevator floor works loose and falls. A. How long will it take the bolt to fall to the elevator floor? I am not sure if I should do this relative to elevator...

Homework Statement Two straight roads intersect at point O and cross at an angle Θ to one another, such that tan Θ = 3/4.Two cars, A and B are traveling towards O on these roads,A at 5 m/s and B at 8 m/s At a certain moment.A is 100 m from the junction and B, on the other road, is 200 m...

So for dielectrics, electric susceptibility (χ) is just the relative permittivity of the dielectric (κ) minus one? => χ = κ -1? Why? Doesn't this mean χ is a completely pointless constant? Just a different way to write κ?

Let's start with a generalized example: 3A + 1B -> 2C For the mole amount next to each molecule, am I always to consider these as relative to one another or absolute? Most of the videos I have seen are describing the above as "for every 3 moles of A and 1 mole of B you get 2 moles of C". I...

Hi there all, I have a personal project I'm working on and since I haven't done any linear algebra in many years I'm not sure what I think is right, is right. I'm also not entirely sure this is the right place to ask but I'm asking more for confirmation/clarification of methodology than...

Homework Statement 280m wide river, destination 120m upstream, river current is 1.35 m/s downstream and the boat speed in still water is 2.70 m/s. What should the boat's heading angle be (relative to the shore)? Homework Equations V_x = Vcosθ V_y = Vsinθ x = V_0 t (starting points set to 0...

Homework Statement Ball 1 is dropped from rest at a height of 10m above the ground. at the same time, ball 2 is thrown straight upward from ground level with an initial speed of 10m/s. Homework Equations find the relative velocity of the balls when they pass each other at t=1...

This isn't really homework its an example, But I need help understanding it to do my homework Homework Statement A destroyer is 500 km due west of a frigate. The destroyer is traveling at 10 km/h in a direction of 30 degrees north of east.The frigate is traveling at 5(2)^(1/2) in a NW...

Homework Statement Two students are canoeing on a river. While heading upstream, they accidentally drop an empty bottle overboard. They then continue paddling for 1 h, reaching a point 2 Km farther upstream. At this point they realize that the bottle is missing and, driven by ecological...

In sauna rooms, people spend time in conditions of air temperature over 90° C (194° F) with a relative humidity near 10%. However, if you stick your arm into liquid water that is at a temperature of 90° C (194° F), you will be severely burned in less than one minute. Give two reasons why...

Gravity and speed through space has an effect on time. Increased gravity = slower time Increased speed = slower time When we look out at the stars and measure their spectrum, we see a red shift. This red shift is the result of the increase in the distance between the source of the light...

This is partially a question and partially me explaining my understanding of c, frames of reference, and relative motion to see if I have it straight. So, c (the speed of light) is always the same when measured by an observer regardless of the intertial reference frame from which it is...

Homework Statement The number of stars around the Sun, within a distance of 17 ly, is 75. The number of galaxies in the local group, within a distance of 4.0 x106 ly from the Sun, is 26. Calculate the average popluation density, per ly3, of stars and galaxies. Homework EquationsThe Attempt...

Homework Statement A 400m wide river flows from west to east at 30 m/min. Your boat moves at 100m.min relative to the water no matter which direction you point. To cross the river, you start from a dock at point A on the south bank. There is a boat landing directly opposite at point B on the...

Homework Statement A jetliner has a cruising air speed of 620mph relative to the air. Part B How long does it take this plane to fly round-trip from San Francisco to Chicago, an east–west flight of 2000 miles each way, if the wind is blowing at 120mph from the west to the east? Homework...

Homework Statement A particle of rest mass m_0 is moving the S-frame at a velocity of u=(c/2, c/2, c/2) . Calculate: a) its energy E and its momentum p in the S-frame b) E' and p' in the S'-frame moving at v=(c/2, 0,0) relative to S Homework Equations v_x = \frac{v_x-u}{\sqrt{1-(v_xu)/c^2}}...

Homework Statement An airplane pilot sets a compass course due west and maintains an airspeed of 220 km/h. After flying for a time of 0.500 h, she finds herself over a town a distance 120 km west and a distance 20 km south of her starting point. Find the wind velocity Homework Equations...

A woman who can row a boat at 6.4 km/h in still water faces a long, straight river with a width of 6.3 km and a current of 3.3 km/h. Let i point directly across the river and j point directly downstream. If she rows in a straight line to a point directly opposite her starting position, (a)...

Implications of the statement "Acceleration is not relative" As a result of the discussion which ensues from this post I hope to understand the implications of this statement: "Acceleration is not relative." First, I think it will be helpful to establish some context. Context point 1: I...

Homework Statement A body consisting of two spheres attached by a 10 meter solid long rod is rolling down a 45 degree incline at one end while rolling up a 45 degree incline on the other end. At the instant when the connecting rod is horizontal the sphere rolling down has the velocity 2 m/s...

Two person have a relative velocity... Each one see other ones time slowing down... We know both will die at the age of 70... Each one will see that the other one is alive when he dies?How?

I was wondering if someone could have a look at my attempt at calculating the resultant vector of 3 forces. Figure is here:http://tinypic.com/view.php?pic=2psrllz&s=6, and from the top down the forces are F1=24,9kN, F2=12,7kN and F3=21kN. The angles are(again from the top down) 56,4°, 15,3° and...

So here is the problem, you are given four liquids, each has a different density. You are not allowed to measure the mass, or the volume. You cannot use any numbers. You have to make an educated guess as to which liquid is denser. The liquids are different colors, so if you pour them into a test...

Determine the required angular velocity $\omega$ of the relative position vector in order to maintain a constant separation distance $r_0$ for two equal masses. What equations are needed for this?

You are on a train traveling east at speed of 14.0 m/s with respect to the ground. if you walk west toward the back of the train, with a speed of 1.4 m/s with respect to the train, what is your velocity with respect to the ground? I got the answer as 12.6 m/s east but is my answer going to...

You are traveling on an airplane. The velocity of the plane with respect to the air is 120.0 m/s due east. The velocity of the air with respect to the ground is 43.0 m/s at an angle of 30° west of due north. 1.What is the speed of the plane with respect to the ground? I got 82.76 by doing...

Homework Statement A ladybug with a velocity of 10.0mm/s [W] crawls on a chair that is being pulled [50deg N of W] at 40.0mm/s. What is the velocity of the ladybug, relative to the ground?Homework Equations pythag theorum component vectors sohcahtoa The Attempt at a Solution Let [N] and [W]...

Homework Statement Studying Special Relativity at the moment, and having a little trouble getting to grips with it. I've got stuck on this question, and was wondering if anyone could clear it up for me? Here's the question: "A rocket is traveling at 0.6c, v, along the x-axis relative to you...

Suppose a beam of light is approaching you from a distant source. As it comes closer to you, it doesn’t hit you; instead it misses you by a 10 meter distance. How can the rate of acceleration of that beam relative to you, be explained(in non-jargon language)? What would the speed of that be...

"Determine the relative distances of each of the planets from the Sun given [...]." Homework Statement Devise methods to determine the relative distances of each of the planets from the Sun given the information available to Copernicus (observable angles between the planets and the Sun...