Relative velocity Definition and 416 Threads

  1. C

    Help with an airplane problem (relative velocity)

    Homework Statement An airplane pilot sets a compass course due west and maintains an airspeed of 218 km/hr. After flying for a time of 0.510 hr, she finds herself over a town a distance 124km west and a distance 16 km south of her starting point. Find the magnitude of the wind velocity (in...
  2. J

    Relative Velocity of two swimmers

    Homework Statement Two swimmers, Alan and Beth, start together at the same point on the bank of a wide stream that flows with a speed v. Both move at the same speed c (c > v), relative to the water. Alan swims downstream a distance L and then upstream the same distance. Beth swims so...
  3. C

    Dynamics Problem, Relative velocity of rigid body in planar motion

    http://wps.prenhall.com/wps/media/objects/3076/3149958/studypak/questions/html/Ch16/9e_16_43.html That is the image of the problem, which includes a solution. PROBLEM- Besides being really confused on their work, the solution they give and the solution in the back of my book are both...
  4. E

    Relative Velocity: Determine Tension in Elevator Strings

    A 3-kg mass is hanging from a 2-kg mass that is hanging from the ceiling of an elevator. The elevator is accelerating upwards at a rate of 2 m/s^2. a) Determine the tension in the string connected between the two masses and also in the string between the ceiling and the upper mass.b) Repeat for...
  5. E

    Calculating Relative Velocity of a Canoe on a River

    Homework Statement A canoe has a velocity of 0.30m/s northwest relative to the earth. The canoe is on a river that is flowing 0.50m/s west relative to the earth. Find the velocity (magnitude and direction ) of the canoe relative to the river. Homework Equations E = earth R = river...
  6. P

    Relative Velocity of Points on Rotating Disc

    consider a disc which is rotating about an axis passing through it;s centre of mass now consider a points on the disc other than the centre of mass which are in line with the centre of mass what is their relative velocity and what is the velocity of one point from other's frame
  7. A

    How can we accurately measure the relative velocity between two moving bodies?

    Suppose two bodies A and B are moving perpendicular to each other with velocities 'a' and 'b'. A with 'a' ^ | | | | | | | | | ---------------------------------------------->B with 'b' Now how would they measure their relative velocitites?As A's velocity in the direction of...
  8. C

    Why Are My Velocity Signs Incorrect in Momentum Problems?

    Attached is P14.2, a simple conservation of momentum problem with relative velocities. I have solved the problem on the second page. My answer is wrong because the signs of the velocities are wrong. I have no idea why. I am very bad at assuming directions and being consistent but I can't figure...
  9. W

    Apply the concept of relative velocity

    I cannot understand how to apply the concept of relative velocity in certaijn questions like the below one the question is Two trains A and B of length 400m each are moving on two parallel tracks with a uniform speed of 72km/hr in the same direction with A ahead of B The driver of B decides to...
  10. M

    Relative Velocity after collision

    "Two balls of the same mass approach each other with a relative velocity of 10 m/s, what is their relative velocity after the collision, which is presumed elastic?" I assumed that the balls have equal and opposite velocities of 10 m/s. Should the individual velocities be 5 m/s and -5 m/s...
  11. A

    Why Is Relative Velocity in Two Dimensions So Confusing?

    I guess this is going to be my worst thread. I'm so sick of this stupid concept "relative velocity" that I'm in no mood to present this thread in my "exemplary style" for which i have been included in the "best homework threads" section. I'm sorry for that, but its true. I have no problems...
  12. L

    Help! I Need a Problem Involving Free Fall & Relative Velocity!

    I have to make up or find a problem that invovles free fall velocity AND relative velocity! Can anyone find/make up a problem for that? HELP!
  13. Oxymoron

    Relative Velocity II: Defining Relative Velocity in GR

    The term "Relative Velocity" has a somewhat vague definition in General Relativity - perhaps it doesn't really have a definition at all! What is the relative velocity of two observers with respect to one another when the spacetime that they are moving in is curved? In SR one compares the...
  14. L

    Calculating Distance Downstream with Relative Velocity

    I can't help but think maybe there's extraneous info?? Question: A rowboat crosses a river with a velocity of 3.30 mi/h at an angle of 62.5 degrees North of west relative to the water. The river is .505 mi wide and carries an eastward current of 1.25 mi/h. how far downstream is the boat when...
  15. M

    Relative velocity question - plane and wind

    Relative velocity question -- plane and wind The distance between two cities A and B is l. An airplane travels back and forth between A and B, flying in a line, with velocity V relative to the air. (a) Find the total flight time, if the wind blows with velocity v, in a direction that forms an...
  16. W

    How to Solve Problems Involving Relative Velocity: Hints and Tips"

    Hello all! My physics teacher has been absent for about two days so i haven't been able to ask him any questions. Basically I don't understand the concept of relative velocity. I couldn't even start one problem! 1) A Jet airliner moving intially at 300 mph due east enters a...
  17. J

    How Does Relative Motion Affect Navigation Strategy in Maritime Pathfinding?

    The question is like that. Q: A ship B is steaming on a straight course south-east at a uniform speed of 15km/h. Another ship A, is a distance of 10 km due north of B and steams at a speed of 12km/h. Find the course that A must steer in order to gets as close to B as possible, and their minimum...
  18. C

    Difficult relative velocity question involving boats

    Here is the question...Two boats are heading away from shore. Boat 1 heads due north at a speed of 3 m/s relative to the shore. Relative to Boat 1, Boat 2 is moving 40° north of east at a speed of 1.7 m/s. A passenger on Boat 2 walks due east across the deck at a speed of 1.1 m/s relative to...
  19. P

    Frames of reference and relative velocity

    :confused: I am in desperate need of help with a certian physice question I am struggling on. here's the question: "A pilot is required to fly directly from london to rome, in 3.5hours. the displacement is 1400km [S 43degrees E]. a wind is blowing with a velocity of 75km/h [E]...
  20. B

    Problems involving frames of reference and relative velocity

    I have a few questions here, and I'm stuck/confused on some of them. Here they are: 1. The air speed of a small plane is 215 km/h.The wind is blowing at 57 km/h from the west. Determine the velocity of the plane relative to the ground if the pilot keeps the plane aimed in the direction [34...
  21. K

    Relative Velocity Rain Fall Problem

    Hi, Can someone please check my work and tell me where I am going wrong? Rain is falling vertically downward with a velocity 25m/s. A cyclist is moving from North to South vith a velocity 15m/s. What is the velocity of the rain with respect to the cyclist? What is the direction the cyclist has...
  22. Oxymoron

    Relative Velocity: General Relativity Views & Choices

    What is everyone's views on relative velocity is General Relativity? Is it useless? Is it useful, if we make specific choices about how we parallel transport? Is there a definite relative velocity? Is there relative velocity at all? Or is there a better one than all the others?
  23. T

    Relative Velocity of Aeroplane from A to B

    An aeroplane starts from airport A to airport B, which is 600km away. The course (N) over ground from A to B is 30°. The wind is blowing with v(W) = 40 km/h from NW. The relative velocity is 200 km/h. can somebody pls explain to me how does the vector diagram looks like?? i don't know...
  24. D

    Relative Velocity Bird Flying Problem

    Hey. I've done this question, but my answer is only partly correct according to the answer book. Heres the question: "To a bird flying at 20km/h on a bearing of 160 degrees, the wind seems to be coming from the south at 25km/h. Find the true velocity of the wind" ok. I said that B is the...
  25. L

    Can You Solve This Relative Velocity Physics Problem?

    could you solve this physics problem an aeroplane is flying in a triangular course of order. the length of each side of the triangle is " a " km and the wind is blowing along its one side with velocity u km/hr . prove that the areoplane will take a*sq.rt of 3(sq.rt of 3 +1)/2u hour to complete...
  26. O

    How Does Wind Affect the Velocity of an Aircraft?

    A jet airliner moving initially at 300 mi/h due east enters a region where the wind is blowing at 100 mi/h in a direction 27 degress north of east. What is the new velocity of the aircraft to the ground? This is how i did it: Vag=Vaw + Vwg Vag=? Vaw(aircraft relative to wind)= 300...
  27. N

    Relative Velocity - I know the answer - But how to arrive at it?

    I have been pulling my hair out over this one. Here is the question: Assume that a river has straight and parallel banks and that the current is 0.75 m/s. Drifiting down the river, you fall out of your boat and immediately grab on to a log. You hold on for 40 seconds, and then swim after...
  28. B

    What is the relative velocity of the airplane to the surface

    ok i have tried to draw this problem several times and i get different answers every time...my answers range from 804-880km/h and i can't get the degree down either...please help... an airplane pilot tries to fly directly east of the velocity of 800.0km/h if a wind comes from the southwest at...
  29. X

    Help with vectors and 2-dimentisonal motion: relative velocity

    A science student is riding on a flatcar of a train traveling along a straight horizontal track at a constant speed of 10 m/s. The student throws a ball along a path that he judges to make an initial angle of 60° with the horizontal and to be in line with the track. The student’s professor, who...
  30. J

    Groundspeed of Plane in 10km/h Headwind: 90km/h

    A plane can fly 100km/h in still air. It flies into a 10 km/h headwind. What is its groundspeed? Would this answer be 100 - 10 = 90km/h? Just making sure i didn't overlook something.
  31. K

    Relative Velocity Q: An Airplane Flying 35° N of E in 100 km/h Wind

    Pretty easy relative velocity question but I suck at Physics. I wanted to check my diagram and if it is not right than ask for help on a mathematical approach because mine is not working. The question is: An airplane, who air speed is 600 km/h, is supposed to fly in a straight path 35.0...
  32. E

    Relative velocity of Electromagnetic waves

    I have a problem that I cannot get the correct answer. An Astronomer observes electromagnetic waves emmitted by oxygen atoms in a distant galaxy that have a frequency of 5.71 *10^14 Hz. On earth, oxygen atoms emit waves that have a freq. of 5.841 *10^14. What is the relative velocity of the...
  33. C

    How Is the Velocity of the Boat Relative to the Earth Calculated?

    A boat is traveling 3 m/s relative to the water due north. A current is flowing 4 m/s due east. What is the velocity of the boat relative to the earth? The length of the river is 1000 m. Ok so I used pythogorean theorem and got 5 m/s. Then how would you find the time it takes for the boat to...
  34. J

    Relative Velocity and Vector Resolution

    You row a boat perpendicular to the shore of a river that flows at 3.0 m/s. The velocity of your boat is 4.0 m/s relative to the water. a. What is your velocity of your boat relative to the shore? b. What is the component of your velocity parallel to the shore? Perpendicular to it? A was...
  35. J

    How Should Direction Be Adjusted in Relative Velocity Problems?

    I have a couple of problems.. I'll show all my work... A swimmer wants to swim due east in a stream that flows due south. In which direction should the swimmer swim? The choices are east, north, northeast, south, southeast, and west... I chose Northeast. Here's another question... use...
  36. J

    Calculating Relative Velocity for Walking on a Treadmill

    You exercise by walking for 15 minutes on a treadmill that has a level track that moves at a velocity of -4km/h. What is your velocity relative to the treadmill? What is your velocity relative to the floor? What is your total displacement relative to the treadmill when you finish...
  37. J

    Relative Velocity in River Navigation: Solving for Current and Boat Speed

    I'm not sure how to do this problem.. please help.. A river flows toward the east. Because of your knowledge of physics, you head your boat 53 degrees west of north and have a velocity of 6.0 m/s due north relative to the shore. a. What is the velocity of the current. b. What is your speed...
  38. G

    How Do You Calculate Aircraft Velocity with Wind Influence?

    Relative Velocity? OK - I'm having problems visualizing a relative velocity problem. Please let me know if I am on the right track... problem involves a jet with initial V of 300 mi/h due east that encounters winds at 100 mi/h in a direction 30 degrees north of east. I need to calculate new...
  39. M

    Solving for Relative Velocity: Helicopter and Ejected Package Collision

    "A helicopter is flying horizontally at 8.1 m/s and an altitude of 16 m when a package of emergency medical supplies is ejected horizontally backward with a speed of 13 m/s relative to the helicopter. Ignoring air resistance, what is the horizontal distance between the package and the helicopter...
  40. R

    Adding & Subtracting Vecots And Relative Velocity

    Adding & Subtracting Vectors And Relative Velocity Hey everyone, I am so confused with this it's not funny. This is my first time accessing a site like thisss, but I am desperate seeing as though it's school holidays atm where I am and I can't talk to my physics teacher for help. Anyhow, I hope...
  41. Link

    Measuring Rotational Speed of Io w/Doppler & Relative Velocity to Jupiter

    I want to measure the rotational speed of Io using a spectrograph, using the doppler formula. Since it is rotating around Jupiter, i have to take the velocity relative to jupiter, but I wonder tough how this is possible when Io is not rotating at an right angle to my observation point. Is there...
  42. C

    How Can a Pilot Adjust Course for Wind to Maintain a Westward Path?

    Hello I am new to this forum and I am desperate, I cannot figure this out, my professor gives us four assignments a year, on subjects that she will not lecture on at all and we have to read and find out on our own and right a report on it and then do four problems she chooses, well in theory I...
  43. D

    How Do Relative Velocity and Relative Path Differ?

    What is relative velocity? I have solved a lot of questions relating to it but I'm still confused what EXACTLY is it? Its in my maths book so my mathematics teacher was not able describe this in detail. One more thing: I'll be much pleased if someone also explains what is relative path. Thanks...
  44. V

    Starships A & B: Relative Velocity & Time Interval

    suppose there are 2 starships, A and B, moving towards each other wuth a relative velocity of 0.999c. they pass each other at time t=t0. after moving a certian distance (relative), they stop(relative to each other), turn around and again statr moving towards each other with the same velocity, of...
  45. T

    How High Does an Object Rise When Thrown Upwards at 20 m/s?

    An object is thrown directly up (positive direction) with a velocity (vo) of 20 m/s and do= 0. How high does it rise (v = 0 cm/s at top of rise). Remember, acceleration is -9.8 m/s2. d =_______________m this is the problem I was given I think I am to use d= do + vot + 1/2atsquared...
  46. F

    Help with Relative Velocity Maths Vector Diagram

    Hmm... This is a chp in a-maths... I appear to be having a mental block regarding the vector diagram thingy... Help me please ? Thx... :cry: :cry:
  47. P

    Relative Velocity: Solving Airplane Vector Problem

    I just found this site, AWESOME. Im having a problem this problem dealing with vectors: An airplane has a veloctiy of 300mph going North of East, and the wind is blowing eastward at a velocity of 100mph at an angle of 45 degrees from east, what is the plane's new velocity? is V naught=...
  48. M

    Relative Velocity as far as I can tell

    Before I get to the problem, Id just like to say a big thank you to all of you who help out and answer all of our questions. While many of them appear basic, to us they are daunting. It's nice to have a place to turn to when your professor barely speaks english and isn't a whole lot of help...
  49. C

    Calculating Relative Velocity on a Moving Ship: Magnitude and Direction

    A man walks with a velocity of 2m/s due North on a ship, which moves due East at 3m/s. Find the relative velocity of the man to the Earth, in magnitude and direction. I do it this way: rel. vel. of man to ship = Vm -Vs Vm = rel. vel. of man to ship + Vs...
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