# Questions tagged [relative-motion]

The tag has no usage guidance.

623 questions
Filter by
Sorted by
Tagged with
98 views

### How can an accelerated frame and a gravitational field be equal?

How can two things that are different be equal? In a gravitational field there is actually gravity that push us down, but in the accelerated frame there is nothing that push us down.
282 views

### Relative velocity related to acceleration

Let's say we have a car moving on the horizontal ground with a velocity of $10 \hat{i} \frac{m}{s}$. A person inside throws a ball vertically upward with a velocity of $3 \hat{j} \frac{m}{s}$. Now I ...
83 views

### A question about relative motion and how to make sense of it

So, here is the question: Assuming the 2D Cartesian system and the basis vectors $\hat{i}$ and $\hat{j}$, we have two cars A and B located at (0,6) and (-30,0) respectively. Car A starts moving with a ...
102 views

### Thought experiment on relative motion

Imagine two persons (A and B) in a vacuum in outer space that are in front of each other and are not in motion. Say that suddenly A starts moving away with a constant velocity from B. In this case, ...
65 views

### Why is light speed constant even in respect of a moving body? [duplicate]

My teacher told that speed of light is constant. The speed of moving object appears 0 when seen by another moving object( of same speed as that of first) but she told that light speed is constant ...
33 views

109 views

### How to calculate relative velocity in curved spacetime?

Is there a nice geometric way to calculate relative velocity in curved space time? I'm looking from something similar to how the separation vector $n$ between $2$ neighboring geodesics obey:  \...
149 views

### I am moving right and rain is falling vertically down.Why should I hold umbrella at an angle?

This is related to relative velocity.I get that, from my moving frame of reference rain is making an angle.But still... it doesn't make sense to hold umbrella at an angle when rain is falling ...
38 views

### If motion is relative, can we say that the Earth doesn't revolve around the Sun? [duplicate]

Considering motion to be relative, consider these two cases as follows An observer is standing on the sun and observing the earth and the earth has no background (no stars and stuff in the background)...
1k views

### How should I understand the idea of relativity of space?

In the book General Physics by L.D.Landau, he mentioned the following in the first and second paragraph The fundamental concept of mechanics is that of motion of a body with respect to other bodies. ...
21 views

### Sliding Friction Force

Sliding friction force is not dependent on velocity. Is wear dependent on velocity? For example, it takes 10 Newtons to overcome sliding friction, no matter if the relative velocity is 1m/s or 1000m/s....
29 views

### Velocity of a swimmer relative to the Earth [closed]

Julia can swim 0.34 m/s in still water. She swims directly east across a river that is 180 m wide and lands at a point that is 81 m north downstream. Determine Julia's velocity while swimming relative ...
63 views

### Velocity of an object with respect to the same object

I know that velocity of an object with respect to the same object is a null vector but I'm not able to get a grasp of it. Whatever I had thought till now is that if I'm sitting in a train (which may ...
43 views

### Relative Motion and Motion on ground

When I walk on the ground I know that it's me who is walking and not that I am just moving my legs forward and backward and the ground is moving.But according to relative motion I should not be able ...
229 views

### What will be the minimum drift possible when a boat crosses a river? [closed]

Imagine a boat with a constant speed $v$ that has to cross a river of width $d$. Let the river flow with a constant velocity $u$. I want to know the angle at which the boat should sail in order to ...
43 views

### Measuring the speed of an object

If I understand correctly someone said (Einstein?) that all motion is relative. However, if it were possible; given that light always travels in a vacuum at a fixed speed, could all other motion be ...
57 views

### How would we know whether a object is moving in deep space?

In deep space, there isn't anything we can compare our position with (According to my knowledge). In other words, we won't be able to define an origin so how would we know whether we are in motion or ...
73 views

### How can we tell if a charge is moving in a Magnetic Field?

In the equation $\vec F=q\vec v×\vec B$ ($\vec B$ is the magnetic field), what is $\vec v$ with respect to? If we were to imagine $\vec B$ to be infinitely large. How could we tell if the charge is ...
90 views

### Why does these two masses not have same acceleration? [closed]

Assumptions: No friction , $m_2$=5kg and $z_1$=2kg. $z_2$ is fixed at its place. Here, there is a mass of $5kg$ on a movable wedge of mass $2kg$. So, my question is that can we say that acceleration ...
84 views

### Acceleration and geodesics in General Relativity

Consider this situation: A) An aeroplane travels a distance from point A to point B which are located on the opposite sides of the Earth. The aeroplane has taken the shortest possible distance to ...
366 views

### Is work done by the internal forces independent of the frame of reference?

This question is about work done being dependent on the frame of reference, which is, obviously the net work done. I ask what is the reason for the work done by internal forces to be independent of ...