# Tag Info

### Forces in tangentially-accelerating circular motion

Consider your experiment of a driver travelling in a circle. Now when you make the free body diagram of the driver, you can notice that the only force acting on the horizontal direction is due to ...

### Resolution of Ehrenfest paradox using only special relativity

Let's say we have a turntable where any point on the perimeter has a instantaneous tangential velocity such that the gamma factor is 2. A ruler placed on the perimeter will length contract to half its ...
• 5,861
1 vote

### Relative acceleration, mechanics

Perhaps it would help to think of relative displacement and relative velocity. Suppose m and M are on the table. Suppose M is at $x_M = -1 \space m$ and m is at $x_m = 2 \space m$. You can say what ...
• 41.1k
1 vote

### Resolution of Ehrenfest paradox using only special relativity

Instead of a solid disk, we might as well think of a circular train traveling on a circular track. Alice sits in the station. Bob is riding on the train. The Question: The track is shorter in Bob's (...
• 15.9k

### Is angular velocity about any point in a rigid body always the same?

Doubt 1 It is measured about the axis of rotation. Doubt 2 Yes. For a rigid body all points will complete one revolution, $2\pi$ radians, about any axis of rotation in exactly the same amount of ...
• 73.6k

### Is angular velocity about any point in a rigid body always the same?

Each part of the rotating disk will have the same angular velocity. However, they will not all have the same tangential velocity (which will increase as you move further away from the axis of rotation)...

### Do you always experience the gravitational influence of other mass as you see them in your frame?

These are excellent questions! They involve the interrelation of various physics concepts. And we would expect physics to be internally consistent, generally speaking. But since your insights are not ...
• 1,148

### Motion of person in bus in inertial and non-inertial frame

A person is sitting in a bus that is moving with constant velocity, due to friction their is no relative velocity between bus and the person. If the bus is moving with constant velocity, no friction ...
• 73.6k

### Motion of person in bus in inertial and non-inertial frame

These effects are often called ficticious forces. I'll often call them pseudo forces, but I have found the best way to think of them is as accelerations. When you do the equations of motion in a non-...
• 50.2k

### Motion of person in bus in inertial and non-inertial frame

What we feel in an accelerating vehicle is the force from the seat back that is pushing us forwards so that we accelerate along with the vehicle. What we unconsciously assume is that there must be an ...
• 56.3k
Accepted

### Motion of person in bus in inertial and non-inertial frame

My doubt is, if the fictitious force is not a real force why do we still feel a force pushing us backward while sitting in accelerating car? If you were somehow levitating in the bus as it ...
• 57.2k

### Motion of person in bus in inertial and non-inertial frame

I think, If you are considering acceleration in any sense, you need to include the reference frame in which the acceleration is taking place. In 2nd person frame of reference, the one observing from ...

### How does brain perceive time dilation due to gravity?

I believe since the person is on another planet with less gravitational force or medium or slightly less and the time to rotate the sun one complete rotation time varies from planet to planet. So ...
A rigid body $B$, by definition, is such that, for every point $O\in B$ there is a triple of orthonormal axes ${\bf e}_1, {\bf e}_2, {\bf e}_3$ centered at $O$ such that the material points $Q$ of ...