Tagged Questions

The tag has no usage guidance, but it has a tag wiki.

50 views

Exertion of force due to spin of Earth

If Earth were to spin at a different speed would I be experiencing a different weight?
56 views

Stored Energy in My Badge Reel Finds Equilibrium With Centrifugal Force?

Probably a most horrible question title, please respond with suggestions for a better one. In the example of my badge reel, I grab hold of my badge itself and pull on the reel until the string is ...
640 views

Rivers that flow “uphill” due to Earth's rotation

One of the fun tidbits that gets bandied around in physics departments is that the Mississippi River actually flows away from the center of the Earth. Due to the Earth's oblateness, the source of the ...
58 views

Why is gravity high at poles but lower inside the surface of Earth, as compared to $g$ on surface? [duplicate]

My high-school physics teacher recently displayed some formulae stating at when we dig deeper the gravity pull is lower but at poles (the flattened part) it is appreciably higher. Now, if we consider ...
82 views

How do cyclonic dust separators work? [closed]

I have a background in engineering so I am somewhat embarrassed to say that I don't understand how a seemingly simple cyclonic dust separator works. Here is a link to video of such a device in ...
85 views

What mistake am I making in plotting this graph of effective potential for the Earth-Moon system?

I am trying to create a graph of effective potential for the Earth-Moon system in Excel. It should result in a graph that looks like this: But this is not what I end up with. (I've made a Google ...
186 views

Gravitational Null Point between Earth and Moon

I need help finding the gravitational null point point between the Earth and the Moon, the point beyond which you start falling towards Moon. I am having difficulty in taking into account the orbiting ...
223 views

Centrifugal force on a pendulum

Why don't we consider the centrifugal force acting on the bob of a pendulum while drawing the Free Body Diagram of a pendulum? It's also a sort of circular motion.
13 views

Direction of acceleration in an oscillating pendulum [duplicate]

Consider an oscillating pendulum hung from a rigid wall. Neglect air friction and all. What's the direction of its resultant acceleration? Radial, tangential or somewhere in between? It should be ...
123 views

What force balances centripetal force of Earth in inertial frame of reference?

I understand that in a non-inertial frame of reference rotating with the Earth, an object at rest has a weight that is equal to mg. This mg is the vector addition of the centrifugal force and the true ...
759 views

Can a pilot in a small spaceship feel G force in space?

I am not really good in physics so I might be wrong at some points, but here is the situation. Consider a spaceship of the size of a fighter plane. And like a fighter plane, the ship is very mobile. ...
38 views

Anti-centrifugal force? [duplicate]

I put some balls (denser than water) in a bucket. I took a stirring rod, and swirled the water in one direction. The water became low in the middle, and high along the edges (centrifugal force). But ...
92 views

Can slow but long centrifugations substitute for fast but short centrifugations?

In many lab protocols, a specific centrifugation rate and time is usually required. For example, DNA precipitation protocols usually require that the precipitated DNA be spun at 12,000 g for 30 ...
1k views

What is an effective potential in classical mechanics?

What is an effective potential in classical mechanics? I have read the wikipedia article and David Tong's lectures notes, but I didn't understand how an effective potential simplifies a situation or ...
61 views

Centrifugal force on objects rotating around Earth

Suppose two objects travel around the equator on Earth at the same speed, $v$, in opposite directions, where the speed $v$ is measured relative to the Earth's surface. Will they experience different ...
564 views

Shape of a rotating fluid surface

I was going through fluid dynamics and I came upon this section on the shape of a liquid surface in a rotating cylindrical vessel. The working in the book is something like this: It considers a mass ...
109 views

The physics behind tilting trains

So I'm trying to get an intuition behind the physics behind banked curves (and tilting trains). I know how to do the calculations, but I'm still struggling with the "why". If I'm sitting in a train, ...
197 views

What forces carry hovering objects around the earth with its rotation?

My questions are: a) What significant forces “carry” flying objects around with the rotation of the earth, b) How do each of those forces contribute to that “carrying”, and c) How relatively ...
80 views

Superluminal speed?

I came by the quotation below. I'm confused: does it mean that it's actually possible for light and even material objects to move faster than light? Gravitational fields are present the velocities ...
820 views

How does the kinetic energy of a ballerina increase? [duplicate]

When a ballerina pulls her arms in, her rotational kinetic energy increases because angular momentum is conserved. That means that work must have been done on her. I saw somewhere that there is work ...
210 views

A very elementary question about centrifugal force

I was recently reading some Newtonian dynamics textbook, and then I came across with a problem about the centrifugal effect on mass free falling to Earth. I can mathematically appreciate the fact that ...
186 views

Since the gravitational force is only attractive, why does matter not just concentrate into a small sphere?

This doubt has been wandering in my head for a long time. The gravitational force is only attractive force not a repulsive force. Since gravitational force is only attractive force, why not the ...
21k views

Is there a huge difference between centrifugal and centripetal forces?

I am doing a video for 8th grade on the subject. I'm showing the experiment of swinging a bucket of water over your head. Is there a huge difference between centrifugal and centripetal forces? Would ...
91 views

How realistic is a “bolas” system for artificial gravity in space travel?

The spinning space-station is very popular in sci-fi as a means of emulating gravity in space. But it requires rather a large diameter to minimise "gravitational gradient" effects and that means such ...
126 views

Why is the water in a cup not inclined (opposite the cup) when the plane takes a turn?

When a aircraft takes a turn: Why is the water in a cup not inclined (opposite the cup)?
453 views

Is it possible to counter-act centrifugal force by moving at the same speed in the anti-spin direction?

I've recently been contemplating things like artificial gravity in a rotating space ship (for example, the O'Neill Cylinder) and learning about the Coralis effect and other interesting fictitious ...
37 views

Consideration of centrifugal force during descent

If we imagine an object falling from a height h above the surface of the earth. We can go into a rotating frame and therefore introduce Coriolis and centrifugal forces. Using the Coriolis force the ...
56 views

The athlete feels a centrifugal force when whirling the hammer - is there always a centrifugal force associated with a centripetal force? [closed]

(this is a homework question) To this, I would say that the centrifugal force is just the reactionary force of the centripetal force, which is causing the hammer to 'want' to move away. Therefore, ...
346 views

Calculating the first cosmic velocity / velocity for a circular orbit

Today in class we calculated first cosmic velocity using this equation $$G\frac{mM}{(R+h)^2}=\frac{mV^2}{R+h},$$ where $m$ = mass of the body, $M$ = mass of the Earth, $R$ = radius of the Earth, $h$ = ...
165 views

Centrifugal Term

I'm studying quantum mechanics with Griffiths (2 nd edition) and I have one question related to the Schrodinger equation in spherical coordinates. In the radial equation: \frac{d}{dr}(r^2\frac{dR}{...
169 views

Would it be possible to make a space elevator only in the atmosphere?

I wonder if with current day technology we could make a "floating platform" which hangs from a satellite by a space elevator. This could allow a "launch process" involving floating a balloon to the ...
216 views

How does a wheel balance itself during circular motion? [duplicate]

A wheel (or any ring of considerable mass) hardly balances itself when it is placed vertically on ground, but when we roll it along the ground it balances itself. What causes this effect? I guess its ...
372 views

Intuitive understanding of Lagrange point L3

I learned about Lagrange points today and the physics behind L1, L2, L4 and L5 make intuitive sense to me. But I'm stumped by L3. Wikipedia says "L3 in the Sun–Earth system exists on the opposite ...
148 views

Why do we use the term 'centrifugal force' to calculate net gravitational force?

When an object, orbiting in circular path, experiences the sensation of being thrown outward away from the centre of circle. We often think that an outward force or centrifugal force is responsible ...
4k views

As a car turns around a circle, why does the force of static friction point towards the center of the circle [duplicate]

A car moves along a flat, circular road. It has a tangential velocity to the road, but the car tires change direction and the car experiences a force of static friction causing a centripetal ...
291 views

Centripetal and centrifugal force

If a stone is rotated with the help of a rope, then both centripetal force and centrifugal force will be liberated. The magnitude of that forces are same, but direction of them are opposite to each ...
62 views

centrifugal force and radius of its circle

If a point starts to travel through a path of circle, then it will must have acceleration. The only reason behind this, the direction of velocity changes always. We already assumed that the value of ...
65 views

Intuition of centrifugal force [duplicate]

I heard that centrifugal force does not really exist; that it is made as opposite substance to centripetal force. Is it true? Could someone define for me what centrifugal force is in terms of vectors ...
993 views

The subtle differences between angular momentum and centrifugal force?

I am a mathematician wanting to understand the differences between the concepts of angular momentum and centrifugal force. The following two ideas are clear to me from a physical point of view, but ...
2k views

Intuition and difference between centrifugal force & Coriolis force?

My book says that when a frame rotates uniformly, pseudo/fictitious force must be taken to count. This is centrifugal force. Also, while Googling, I found another pseudo force Coriolis force. ...
73 views

Rigid bar on the floor of a rotating space station

I read this in a comment to an answer in physics.stackexchange.com. The comment was An easier method might be to just place a straight, rigid beam on the floor. If you find the floor is concave, ...
95 views

What if the centripetal force were acting outward?

Centripetal force is the centre-seeking force & is responsible for circular motion. But what if the centripetal force were acting radially outward? What would happen then?
40 views

Why are centrifuge space-station designs not a reality? [duplicate]

Considering how useful it could be for the crew of a space station to have at their disposal a 1g environment (or more) at the rim to a 0g environment at the axis of rotation, why aren't modern space ...
287 views

Who plays the role of centrifugal force in an inertial frame of reference?

It is noteworthy to quote a sentence from my book, It is a misconception among the beginners that centrifugal force acts on a particle in order to make the particle go on a circle. Centrifugal ...
544 views

Centrifugal force in the Hydrogen atom for $L=0$

I have found the following interesting article: http://arxiv.org/abs/0706.0924 The authors examine the radial momentum operator in detail, in particular its time evolution due to the forces acting ...
329 views

How to correctly resolve forces radially in vertical circular motion?

I have always had problems at resolving forces and relating to Centripetal Force. Il show an example that I am stuck at right now. Please help me understand. This is the diagram: This is the ...
31k views

Why is Earth's gravity stronger at the poles?

Many sources state that the Earth's gravity is stronger at the poles than the equator for two reasons: The centrifugal "force" cancels out the gravity minimally, more so at the equator than at the ...
36 views

Correcting for oblateness of the Earth [duplicate]

I'm trying to model numerically the effects of the Earth's oblateness on satellite orbits. I'm seeing precession of the orbit, but not in the plane that I'm expecting. Here's my corrected grav. ...