# What is Galilean relativity: Definition and 33 Discussions

Galilean invariance or Galilean relativity states that the laws of motion are the same in all inertial frames. Galileo Galilei first described this principle in 1632 in his Dialogue Concerning the Two Chief World Systems using the example of a ship travelling at constant velocity, without rocking, on a smooth sea; any observer below the deck would not be able to tell whether the ship was moving or stationary.
The young Albert Einstein "was engrossed in analyzing Galileo's principle of inertia (Galilean relativity)".

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1. ### I Galilean relativity for 2 frames

Learning Galilean transformation and just want to see if I understand the concept well. both frames are moving relative to some other frame(me standing all the time, not moving). frame A moving 5m/s, frame B moving 7m/s, which in turn means frame B moving 2m/s relative to frame A. Galilleo...
2. ### I Galilean relativity in terms of homogeneity

I have a question related to Landau's book. In that, he says: As an example, I'd like to bring a car and the ball hung inside the car and we can look at it from 2 different frames of reference. Frame of reference is me(I'm inside the car): If car moves with constant speed, nothing happens to...
3. ### I Can time be another basis vector under Galilean relativity?

I refer to the video of this page, where there is a description of Galilean relativity that is meant to be an introduction to SR, making the comprehension of the latter easier as a smooth evolution from the former. All the series is in my opinion excellent, but I think that this aspect is...
4. ### I Proving Galilean Transformation for Inertial Frames

I know we can prove that a Galilean transformation sends one inertial frame to another inertial frame, by proving ##\frac{d^2 f(\vec{r})}{d(f(t))^2} = \frac{d^2 \vec{r}}{dt^2}##, but can we prove the reverse? Can we prove that if the acceleration seen in two frames are the same, then the...
5. ### Finding the velocity of a car in a different frame of reference

Here's what I did so far. The velocity of the first car is ##v = v_0 +at## Frame of reference S = the road Frame of reference S' = the second car thus, v' is the speed of the first car in the frame of reference S' and v the speed in the frame of reference S. Here's what make me doubt. The...
6. ### "Distance" between events in uniformly moving and accelerating frames

(1) Uniformly moving frames I begin with a drawing of the situation. The events are labelled as ##\color{red}{E_1}## and ##\color{red}{E_2}##. We note the time of those events : ##t_1 = t'_1 = 30s## and ##t_2 = t_2' = 30+60 = 90s##. I attempt the problem in two different ways. (a) By...
7. ### Does Galilean relativity imply infinite propagation speed?

Without assuming a universal speed that is constant in all inertial reference frames, is it a necessary consequence of Galilean symmetry that interactions are instantaneous? If this is the case how can we prove this?
8. ### Reference frames and Galilean transformation

Homework Statement I am having a issue relating part of this question to the Galilean transformation. Question Relative to the laboratory, a rod of rest length ##l_0## moves in its own line with velocity u. A particle moves in the same line with equal and opposite velocity . How long dose it...
9. ### Should the non-relativistic Navier Stokes Equations be modified?

Choking mass flow seems to reflect the fact that fluid momentum density has a maximum value (in stationary conditions) equal to ##\rho_* c_*## where ##\rho_*## is the critical mass density and ##c_*## is the critical velocity, which is closely related to the speed of sound (see...
10. ### Galilean Relativity Problem

Homework Statement P and M are each riding Ents while playing catch with two rings. P throws his gold ring with a speed relative himself that is twice the speed that M throws his silver ring relative to himself. P and M start off going with the same speed and direction, 30m apart with M in...
11. ### Galilean Relativity (Invariance) Problem

Homework Statement Imagine two inertial frames, S and S'. Inertial frame S' moves with velocity v0 = 5 m = s in the upward (positive y) direction as seen by an observer in frame S. Now imagine that a person at rest in frame S throws a ball with mass m straight up into the air with initial...
12. ### B Is energy Galilean invariant

As the title says, is energy Galilean invariant? I'm fairly sure it isn't, since if one considers the simple case of a free particle, such that its energy is ##E=\frac{p^{2}}{2m}##, then under a Galilean boost, it follows that ##E'=...
13. ### A problem regarding Galilean relativity

Homework Statement Two bodies are moving on the same line. When they move away from each other the distance between them changes for 16m in a time interval of 3 s (Δd1 = 16 m ; Δt1 = 3 s). When they move towards each other the distance between them changes for 3 m in a time interval of 3 s (Δd2...
14. ### I Galilean Relativity: Can Experiments Tell Motion Relative to Other Frames?

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...
15. ### Does the bullet reach its target?

Homework Statement As outlaws escape in their getaway car, which goes 3/4c, the police officer fires a bullet from a pursuit car, which only goes 1/2c. The muzzle velocity of the bullet (relative to the gun) is 1/3c. Does the bullet reach its target according to Galileo? According to Einstein...
16. ### Galilean Relativity: Different Frames, Different Results

I thought of explaining galilean relativity to a layman like this: "A person is heavily drunk and he revolves, revolves and revolves. He shouts," The world is revolving around me". You are bystander and u say," you drankard, the world is not revolving, but you are the one who is going in rounds...
17. ### Insights The Speed of Light and of Galilean Relativity - Comments

klotza submitted a new PF Insights post The Speed of Light and Galilean Relativity Continue reading the Original PF Insights Post.
18. ### Relativity of position and velocity in classical mechanics

I'm currently collating my own personal notes and would really appreciate some feedback on my description of the relativity of position and velocity in classical mechanics. Here is what I have written "Position is clearly a relative quantity as two inertial frames S and S' displaced by a...
19. ### Speed of particle Galilean relativity

Homework Statement Two particles are created in a high-energy particle accelerator and move off in opposite directions. The speed of one particle, as measured in the laboratory, is 0.650 c, and the speed of each particle relative to the other is 0.950 c, where c = 3 × 108 m/s is the speed of...
20. ### Galilean Relativity and Newton's Laws

I'm a little bit confused about the relationship between Galileo's Principle of Relativity and Newton's Laws. Indeed, as I understand, the Galilean Principle of Relativity is what Galileo presented with Salviatti's ship discussion. The discussion seems to lead to a simple idea: "if one performs...
21. ### Galilean Relativity & Kinetic Energy

How would one find the reference frame in which an object [which undergoes a perfectly inelastic collision with a second object] experiences no change in its kinetic energy?
22. ### Galilean Relativity Question

Homework Statement I came across this problem in a worksheet and I am completely lost as to where to start; can someone help? The question is: Two trains are heading at the same speed, relative to the Earth, in opposite directions. A bomb explodes on each train, but not at the same times...
23. ### Solving the "Paradox" in Galilean Relativity

seems to be a "paradox" in galilean relativity Hello I'm having a little bit of trouble with so-called rest frames. I will distinguish two cases. consider frame S, and a particle moving along the x-axis at speed v. Case I: consider the rest frame S' traveling along with x at speed v...
24. ### Galilean relativity and acceleration

Hello all. I'm a long time reader and a first time poster. I should start by saying that I am not a physicists or a physics student and am studying it merely out of curiosity so please forgive any ambiguous terms I may use that are not standard. I came up with a sort of thought experiment to do...
25. ### Galilean relativity vs special relativity

I was told in another thread that saying that the Galilean relativity of Newtonian and classical mechanics could be thought of as light speed having the possibility of being infinite was nonsense. Since it was true that a discussion there of these points was off-topic, I use this new thread to...
26. ### Momentum and Energy and Galilean Relativity

Homework Statement Suppose you have two bodies (assume a unit mass) approaching one another at the same speed, i.e., the velocities, v, have the same magnitude but are in opposite directions. Presumably the center of mass is half way between them, and it is not moving. It appears that the...
27. ### Galilean Relativity & Inertial Frames

I just want to make sure I understand this correctly. Please critique: Under Galilean relativity, Newton's Law of Inertia retains the same form under any inertial frame of reference. There are relative velocities between inertial frames but its possible to determine absolute velocities under...
28. ### Solve Galilean Relativity Homework: Find Staple Distances

Homework Statement An assembly line has a staple gun that rolls to the left at 1.0 m/s while parts to be stapled roll past it to the right at 3.0 m/s. The staple gun fires 10 staples per second. How far apart are the staples in the finished part? Homework Equations r = r' + Vt The...
29. ### Galilean Relativity & Inconsistency with Classical Physics

Hi, I am a novice here and i am trying to solve the following problem: 1.Show that Galilean relativity transformation produces inconsistent classical physics result when used with equation of expansion of light sphere. (2 different frames) 2. x2 = x1 - vt1 y1 = y2 z1 = z2 t1 = t2...
30. ### Galilean relativity problem

2 trains are traveling at constant speeds on 2 parralel straight line. The first A is traveling at 5m/s the second B is traveling at 2 m/s. An observer at the station observes both trains. At a given instant of time, a passenger in A, a passenger in B and the observer at the sation are all...
31. ### Galilean Relativity: I can't figure this out

Here is the problem: "A passenger in a convertible throws a ball up into the air. The car is going 35.0 m/s. The upward velocity of the ball is 8.00 m/s. Give the equations which specify the ball position at any given time with respect to the passenger (prime values) and respect to an observer...
32. ### Newton's bucket and Galilean relativity

I'm re-reading Greene's The Fabric of the Cosmos. He describes Newton as explaining his (Newton's, not Greene's!) thought experiment of the bucket by the existence of absolute space: something with respect to which rotating objects rotate, even in seemingly empty space. Did Newton ever...
33. ### Galilean Relativity and Tangential Acceleration

Any help would be greatly appreciated. 1. Two swimmers, John and Emma, start together at the same point on the bank of a wide stream that flows with the speed c (c>v), relative to the water. John swims downstream a distance L and then upstream the same distance. Emma swims so that her motion...