What is Relative velocity: Definition and 413 Discussions

The relative velocity







v
→




B
∣
A




{\displaystyle {\vec {v}}_{B\mid A}}
(also







v
→




B
A




{\displaystyle {\vec {v}}_{BA}}
or







v
→




B
rel
⁡
A




{\displaystyle {\vec {v}}_{B\operatorname {rel} A}}
) is the velocity of an object or observer B in the rest frame of another object or observer A.

View More On Wikipedia.org
Recent contents Top users
  1. H

    Relative Velocity - Mistake in Textbook?

    I am just reading through this free online textbook and it seems to me that there is a mistake on page 24. http://www.anselm.edu/internet/physics/cbphysics/downloadsI/cbPhysicsIa18.pdf#page=23 He describes the muzzle velocity, which he defines as the relative velocity between two objects...
  2. R

    Relative velocity of electron moving

    an electron is moving with a velocity of 0.85c in the same direction as that of photon.the relative velocity of the electron with respect to photon is... and why?
  3. A

    Relative Velocity, Rigid Body Kinematics

    Homework Statement W(oa) = -5k α(oa) = 3k B = 30 deg B(dot) = -2cos 30i + 2sin30j = Vrel b(double dot) = 4cos30i - 4sin30j) Homework Equations Va = Woa x Rao + Vrel The Attempt at a Solution This is such a simple problem and I don't know why I am messing it up. I am just...
  4. D

    Average relative velocity in calculating mean free path

    Hello, Does anyone know why we use the root mean square of the relative velocity in calculating the mean free path? As is done in this example: http://galileo.phys.virginia.edu/classes/152.mf1i.spring02/MolecularCollisions.htm Seems like it would make more sense to find the mean of the...
  5. A

    Relative velocity with respect to image in the mirror

    Homework Statement As shown in the figure, a man is running towards left with constant velocity of 7 m/s. Also, a flat vertical mirror is moved to the right with constant velocity of 9 m/s. Calculate the relative velocity between the man and his image. Express your answer in...
  6. C

    Relative velocity and speed of light

    1) On a recent exam, one of the questions asked to find the minimum speed at which you would have to fire two protons head-on if you wanted them to get them within 10^-15m. To make things a bit easier, I treated one proton as being stationary and then found the energy needed to bring the other...
  7. I

    Relative Velocity: Jack & Particle - v to V

    First, a really basic one: if Jack is jogging past me with a constant speed, and I observe that speed to be v in my frame, with what speed will Jack observe me to be moving, as measured from his own frame? If the answer is not v, which Lorentz transformation do I use to derive it? Second, a...
  8. DiracPool

    Does Velocity or Acceleration Determine the Energy of a Moving Object?

    Is the energy gained by a particle moving at a high velocity a product of acceleration or can it arise in an object moving at constant velocity? I mean...OK, thought experiment. I haved a 100 GeV spherical mass moving through space relative to the Earth at 10 m/s. I now accelerate that mass...
  9. Saitama

    The question is: What are the limits for theta and is the working correct?

    Homework Statement (see attachment) Homework Equations The Attempt at a Solution Consider the system at time t (see attachment, I am representing the blocks as point masses) The component of acceleration along the string is ##a_0\cos \theta##. This is the acceleration of the...
  10. N

    Determine the angular velocity and the relative velocity

    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...
  11. coktail

    Are descriptions of relative velocity arbitrary?

    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...
  12. A

    Relative velocity of light in special theory of realtivity?

    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...
  13. A

    Relative Velocity: How Far Will the Boat Move Downstream Without Correction?

    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...
  14. W

    Relative Velocity with plane and wind

    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...
  15. W

    Relative velocity boat crossing a river

    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...
  16. T

    Relative Velocity of Bolt in Elevator

    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...
  17. W

    Relative velocity at a junction

    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...
  18. L

    Relative Velocity of Balls: Solving for t=1 sec

    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...
  19. W

    How Do Relative Velocities Determine Collision Courses?

    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...
  20. T

    What is the Correct Setup for River Relative Velocity Homework?

    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...
  21. T

    Relative velocity of river flowing

    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...
  22. T

    Finding Wind Velocity for a Westward-Bound Airplane

    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...
  23. P

    Problem pertaining to relative velocity and vector components

    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)...
  24. I

    Why is convection heat transfer rate independent of relative velocity?

    Convection heat transfer rate decided by Newton's cooling law doesn't have a relative velocity between the fluid and the solid surface term. But intuitively doesn't blowing faster on a hot surface make it cool quicker?
  25. J

    How Do Velocities Affect Collision and Proximity in Particle Dynamics?

    1.Two particles A and B have velocities 3i and vj respectively (in m/s). (a) Find the position of B relative to A for all t given that r (b relative to a) (t=0) = -9i+6j (in metres). (b) Find the value of v such that A and B collide. (c) If v=1 m/s, find the time and distance when A and B are...
  26. F

    Time dilation effects of relative velocity vs gravitational force?

    I've been wondering.. If a person (A) is, say, on top of Mt. Everest, he would be moving faster than a guy (B) at the foot of the mountain since A is further from the center of the earth, but he would also be experiencing a weaker gravitational force than B. So, for which of the invidividuals...
  27. U

    Equations for relative velocity

    hello everyone, Can someone kindly show me the equation for relative velocity calculations? when i search for them via wikipedia, there is only one formula for collinear objects and they move to the same direction... so what if they move opposite to each? and what if their motions...
  28. M

    Relative velocity video (review and rate)

    Hey Guys I am making a series of physics tutorials.. with an aim to solve problems and understand concepts without making using of any formulae by making use of animations and some real life examples I started with conceps of relative velocity.. Please tell me if its useful.. I am sorry...
  29. P

    OL Exam Question on Relative velocity

    correction -->it should be a high-level exam question. Homework Statement Two ships A and B move with constant speeds 48 km/h and 60 km/h respectively. At a certain instant ship B is 30 km west of A and is traveling due south. Find (i) the direction A should steer in order to get as close as...
  30. C

    Relativistic relative velocity

    Hi. I'm reading some quantum field theory and I'm a bit rusty in my relativistic kinematics. I stumbled across the formula E_1E_2 v_{rel} = ((p_1p_2)^2 - m_1^2m_2^2)^{1/2} where 1 and 2 are two collinearly colliding paritcles with their respective masses and v_{rel} are their relative...
  31. L

    Relative Velocity Problem - Finding an angle of a boat going down a river

    Homework Statement A boat is capable of a constant speed of 4 m/s in a river that is flowing at 2 m/s. If the captain wishes to land 10m downriver while crossing a 50m river, then at what angle should the boat be aimed? Homework Equations...
  32. F

    Relative Velocity Derivation from Maxwell-Boltzmann

    Hi, I have a specific question about the derivation of the relative velocity between two molecules A and B from the Maxwell Boltzmann distribution (which should equal square root of 2 times the average velocity). In equations, I have been evaluating this integral: \begin{eqnarray*}...
  33. I

    Relative velocity practice exam question

    Homework Statement I would like to check my answers for #3 on this practice exam: http://cyclotron.tamu.edu/dhy/sample_exam1_phys218.pdf Homework Equations The Attempt at a Solution b) v(plane-wind)x = 30cos30 v(plane-wind)y= 30sin30 + 160 c) 8.44° East of North d) 1.4...
  34. T

    Calculating Horizontal Component of Raindrop Velocity on Moving Train

    Homework Statement When a train's velocity is 12.0 m/s eastward, raindrops that are falling vertically with respect to the Earth make traces that are inclined 30.0 degrees to the verical on the windoes of the train. A. What is the horizontal componenet of a drop's velocity with respect to the...
  35. 3

    How Do You Calculate the Impact Point of a Bomb Released from a Moving Airplane?

    I'm having problems with this question. I don't know how to solve it...I've usually solved questions with some sort of resistance force but this I don't know how to solve. How would I solve this question? 1. The problem A bomber flies horizontally with a speed of 275 m/s relative to the...
  36. D

    Relative velocity between two accelerating observers

    Suppose two observers A and B are accelerating at the same rate with respect to an inertial reference frame. In A's frame, does B move at a constant velocity? I'm pretty sure (but not certain) that the answer is yes, but even if it is I can't think of a justification.
  37. K

    Does Q remain stationary with respect to P all the time?

    A body is rolling without slipping. Let P be topmost point at an instant and Q bottom-most point at that instant..Is it true that Q remains stationary with respect to P all the time? What i thought was the purely mathematical thing. P will have velocity 2v to right and Q will have 0 velocity...
  38. W

    Conservation of Momentum and Relative Velocity

    Homework Statement A 55kg student stands on a 4.6 kg surfboard moving at 2.0 m/s [E]. The student then walks with a velocity of 1.9 m/s[E] relative to the surfboard. Determine the resultant velocity of the surfboard, relative to the water. Neglect Friction. Answer: 0.25 m/s[E] Homework...
  39. binbagsss

    Relative Velocity Problem: What is the True Velocity of the Wind?

    When a women cycles N at 40kmh^-1, the wind appears to be blowing from a E direction, however when she cycles S at 50kmh^-1, the wind appears to be blowing from the SE. Find the true velocity of the wind. My attempt is attached - I have tried to solve through components and usingthe fact...
  40. D

    Relative velocity inside a train

    Hello Everybody! I have a question - If I'm standing inside a train and I jump up in the air I will land in the same place, I think. Likewise, if I'm holding a pen in my hand and I throw it up in the air it will land again in my hand. But if I stood on top of the train, on the roof, and I...
  41. S

    What is the difference between relative velocity and resultant velocity?

    relative velocity and resultant velocity?also in a connected(with strings) pulley system,how can we calculate the acceleration and velocities of the pullies and the masses connected onto it?
  42. F

    Finding relative velocity when there are multiple unknowns

    Homework Statement Two spaceships, each measuring 300 m in its own rest frame, pass by each other traveling in opposite directions. Instruments on board spaceship A determine that the front of spaceship A requires 1 microsecond to traverse the full length of B. What is the relative velocity...
  43. B

    Can someone explain the concept of relative velocity in physics?

    At the present moment, I am reading a section in my physics textbook concerning relative velocity. In an example the author provides, he states that two trains are traveling in opposite directions at a speed of 80 km/h; and relative two each other they are traveling at a speed of 160 km/h...
  44. M

    Calculating Relative Velocity in a Rotating Beam System

    I've attached a drawing, simplified of the layout of the system I'm working on. I've figured out a function to give me the length of the beam 'x' for a given angle, easy enough, but i need to know the velocity that the end of the rotating beam moves relative to the lower fixed end, so the rate...
  45. T

    Is Relative Velocity Crucial for Rocket Launch Direction?

    Homework Statement explain how relative velocity is related to the direction in which rockets are launched...
  46. T

    How to Calculate Relative Velocity and Force for a Moving Plane and Carrier?

    Homework Statement Hey guys, I've attached the question. Homework Equations The Attempt at a Solution m=3000kg s=75m F thrust = 22000 N v_plane = v_carrier + v_plane/carrier v_plane = v_carrier + (240/3.6) not sure where to go with forces...
  47. B

    Addition of 2-D vectors and relative velocity

    Homework Statement A plane must fly to a destination located due north from its departure point. A gentle wind is blowing from the south-west. What direction must the plane point to reach its destination? Homework Equations The Attempt at a Solution...
  48. R

    How to solve SUVAT problem without using relative velocity

    Homework Statement Calculate the time taken for particle A to catch up with particle B. See attachment for variables. I worked out the answer by finding the relative velocity of A wrt B but apparently there's another method I should have/could have used to solve it? Homework Equations...
  49. S

    Relative velocity of river flow question

    Homework Statement A river is flowing 4.0 m/s to the east. A boater on the south shore plans to reach a dock on the north shore 30.0 Degrees downriver by heading directly across the river. What should be the boat's speed relative to the water? Also, what's the boat's speed relative to the...
  50. M

    Optimal Direction for Long-Distance Swimmer in Ocean Currents

    Homework Statement A long-distance swimmer is able to swim through still water at 4 km/h. She wishes to try to swim from Port Angeles, WA, due north to Victoria, B.C., a distance of 50 km. An ocean current flows through the Strait of Juan de Fuca from west to east at 3 km/h. In what...
Back
Top