The tag has no wiki summary.

learn more… | top users | synonyms

41
votes
7answers
4k views

Why is the Earth so fat?

I made a naive calculation of the height of Earth's equatorial bulge and found that it should be about 10km. The true height is about 20km. My question is: why is there this discrepancy? The ...
29
votes
9answers
6k views

Why doesn't a bike/bicycle fall if going with a high speed?

Why does a bike/bicycle fall when its speed is very low or close to zero and is balanced when going with a high speed?
6
votes
2answers
539 views

Why don't we consider centrifugal force on a mass placed on earth?

Let us say a block of mass is placed on the surface of earth. Then while drawing the forces on that body, we say: Force $F = mg$ acting towards the center of Earth. Normal reaction $N$ offered by ...
6
votes
3answers
683 views

Will a machine or a technique ever be possible that allows artificial gravity in interplanetary space?

Will a machine or a technique ever be possible that allows artificial gravity in interplanetary space? And I ask out of pure curiosity. I know there is the "Vomit Comet" that allows for a non-gravity ...
4
votes
4answers
9k views

How does centrifugal force work?

I know what centrifugal force is, but how does it work? Why are things forced to the outside?
10
votes
1answer
7k views

Derivation of the centrifugal and coriolis force

I was wondering how easily these two pseudo-forces can be derived mathematically in order to exhibit a clear physical meaning. How would you proceed?
4
votes
2answers
1k views

“Artificial gravity” on a rotating space stations

There have been a lot of sci-fi shows recently using the "rotating space station" explanation for gravity on space stations. After watching these videos: ...
30
votes
4answers
6k views

Why can't we feel the Earth turning?

The Earth turns with a very high velocity, around its own axis and around the Sun. So why can't we feel that it's turning, but we can still feel earthquake.
3
votes
2answers
606 views

Centrifugal Force and Polar Coordinates

In Classical Mechanics, both Goldstein and Taylor (authors of different books with the same title) talk about the centrifugal force term when solving the Euler-Lagrange equation for the two body ...
1
vote
3answers
3k views

If the earth would stop spinning, what would happen?

What would happen if the earth would stop spinning? How much heavier would we be? I mean absolutely stop spinning. How much does the centrifugal force affect us? If you give technical answers (please ...
0
votes
3answers
240 views

Will an object resting on a rotating platform move in a frictionless world?

Imagine that a pebble is placed on a uniformly rotating, frictionless disk. What will happen to this pebble? Will the disk slide under it and the pebble stay as is? Or will there be a centrifugal ...
6
votes
2answers
537 views

Confusion with derivation of fictitious forces

I read the mathematical derivation of fictitious forces on Wikipedia and I'm having trouble understanding it. I went on a few other sites looking for a better derivation, but they're all basically the ...
1
vote
2answers
55 views

Centrifuge speed of an object higher than a stationary orbit

In the question At what altitude above equator do gravitational and centrifugal forces cancel each other?, I asked how high a tower on the equator has to be such that at its top, gravitational and ...
1
vote
3answers
839 views

How the apparent weight varies due to the rotational motion of Earth?

I learned that as the earth rotates about its axis, the bodies on the earth also follow a circular path. In most books I read, they give the example of a person standing on a weight balance at the ...
1
vote
2answers
492 views

Intuitive understanding of centripetal vs. centrifugal force

I am having trouble understanding how centripetal force works intuitively. This is my claim. When I have a mass strapped on a string and spin it around, I feel the mass pulling my hand. So, I want ...
46
votes
8answers
7k views

Does centrifugal force exist?

Currently in my last year of high school, and I have always been told that centrifugal force does not exist by my physics teachers. Today my girlfriend in the year below asked me what centrifugal ...
9
votes
6answers
24k views

Gravity on the International Space Station

We created a table in my physics class which contained the strength of gravity on different planet and objects in space. At altitude 0(earth), the gravitational strength is 100%. On the moon at ...
10
votes
3answers
1k views

Centrifugal force?

Everyone calls it a pseudo force and that it is not really present, even there are so many machines listed to advantage of centrifugal force ( centrifuge, washing washing drier),and also it has the ...
4
votes
3answers
131 views

Why is Earth's gravity stronger at the poles?

Lots of places 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 ...
3
votes
2answers
2k views

Fictitious forces confusion

I have a hard time understanding the subject of fictitious forces. Let's discuss a few examples: 1) I'm sitting inside a vehicle which is accelerating in a straight line. I feel like someone is ...
2
votes
4answers
651 views

Do centripetal and reactive centrifugal forces cancel each other out?

In order for a body to move with uniform velocity in a circular path, there must exist some force towards the centre of curvature of the circular path. This is centripetal force. By Newton's Third ...
2
votes
2answers
226 views

Centripetal force in frame of reference of body moving In a circle

Suppose a body is moving in a circle about a fixed point. In the frame of reference of the body, is the centripetal force felt or is only the centrifugal force felt? More generally, does a body only ...
0
votes
0answers
31 views

Could an object higher than the stationary orbit be returned to the outgoing point on this orbit?

In the question Centrifuge speed of an object higher than a stationary orbit, I asked: Does an object higher than the stationary orbit move slower or faster around the world than the top of a tower ...
0
votes
2answers
83 views

At what altitude above equator do gravitational and centrifugal forces cancel each other? [closed]

How high has to be a tower at equator to get on its peak the same - but of course inverted sing - value of gravitational and centrifugal forces?
3
votes
2answers
368 views

Mixing a cup of tea and break of centrifugal force [duplicate]

Possible Duplicate: Vortex in liquid collects particles in center Why when you mix a cup of tea with a teaspoon, tea-craps collect in the center of cup, instead of goes near the walls?
2
votes
3answers
2k views

Why did they add a Centripetal Force in the Free-Body Diagram?

problem ! solution ! Why do they have the centripetal force in there? I understand that the normal force is the centripetal force here, but why would they say "or $\frac{mv^2}{r}$"? I thought it ...
0
votes
1answer
247 views

Centrifugal force acting on ring [closed]

Take for example the case of a rod rotating about an axis passing through its centre of mass and perpendicular to it. It has a ring hung from one of its sides. The rotation of the rod causes the ring ...
0
votes
1answer
421 views

Condition for circular orbit

I am a little confused about the condition for circular orbit. Goldstein's Classical Mechanics has the condition for circular orbit as $$f'=0\tag1$$ where $f'$ is the effective force. I understand ...
0
votes
3answers
2k views

Centripetal/Gravitational Force

Suppose a satellite is orbiting the Earth. The gravitational and centripetal force supposedly point towards the Earth. Therefore, the net force is towards the Earth. Since the satellite doesn't fall ...