What is Equator: Definition and 101 Discussions

The Earth's equator is an imaginary planetary line that is about 40,075 km (24,901 mi) long in circumference. The equator divides the planet into the Northern Hemisphere and Southern Hemisphere and is located at 0 degrees latitude, the halfway line between the North Pole and South Pole.In spatial (3D) geometry, as applied in astronomy, the equator of a rotating spheroid (such as a planet) is the parallel (circle of latitude) at which latitude is defined to be 0°. It is the imaginary line on the spheroid, equidistant from its poles, dividing it into northern and southern hemispheres. In other words, it is the intersection of the spheroid with the plane perpendicular to its axis of rotation and midway between its geographical poles.
When the Sun is directly above the Earth's equator (on the equinoxes of approximately March 20 and September 23), sunlight shines perpendicular to the Earth's axis of rotation, and all latitudes have a 12-hour day and 12-hour night. On and near the equator sunlight comes from almost directly above every day year-round, and thus the equator has a rather stable daytime temperature the whole year.

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  1. P

    If there was a zero net acceleration at the equator?

    Homework Statement How long would a day have to be on Earth if there was zero net acceleration at the equator? Homework Equations Ac=v^2/r Vrotational=Ac / Radius of earth g = 9.8m/ss T = Earth's circumference / rotational velocity V= SQRT(Ac*R) Earth's Radius = 6.37x10^6 Earth's...
  2. L

    A woman has a large stone in her yard. She lives at the equator and

    A woman has a large stone in her yard. She lives at the equator and the date is September 21st. It is midnight and she is thinking of moving the stone. She wants to know, as a fraction of its current weight, how much lighter the stone will be if she waits until noon to move it. Here are some...
  3. Philosophaie

    Lunar solstice when the Moon's Equator crosses the Zero Plane of the Earth

    Is there such a thing as a Lunar solstice? When the Equator of the Moon crosses the plane of the tilt equals zero or the plane of the earth. This should occur when the True Anomaly of the Moon is at approximately 90 Degrees or 270 Degrees depending upon the Moon's Eccentricity. The...
  4. D

    Position of Sun at noon between the Equator and Tropic of Cancer

    In the temperate latitudes of the northern hemisphere, the sun is due south when it reaches the highest point in the sky (see for example http://www.solarplots.info/pages/definitions.aspx" ). What about latitudes between the Tropic of Cancer and the equator? Is the sun due north when it reaches...
  5. H

    Why Earth is Bulged at the Equator

    Why is Earth bulged at equator ? Please don't explain in terms of centrifugal force
  6. A

    What trajectory would have a bullet if fired from equator in a straight line

    I think this is a simple question but I cannot find the answer on the Internet. What trajectory would have a bullet if fired in a straight line towards space from the equator? 1- Assuming there is NO gravity involved, 2- Considering that the bullet is going at a constant velocity, 3-...
  7. K

    Spinning at the North Pole: Equator to Arctic Teleportation

    If You are suddenly teleported from the equator to the north pole. How fast and which way will you be spinning relative to your surroundings?
  8. B

    Calculating Apparent Weight Difference Between Equator and South Pole

    Hello all, just a few problems that I've worked through, just clarifying if I'm on the right track. Thank you in advance. 1.) The radius of the Earth is 6378.1 km and completes one revolution per day. Calculate the difference in apparent weight between a person of 65kg mass, standing on the...
  9. B

    Why do we weigh less at the equator?

    Hello all, I was just bugged by the fact that you weigh more at either of the poles than you do at the equator. I reason that because at the equator you feel the Earth spinning about it's axis, you would feel an additional centripetal force toward the centre of the Earth ontop of the...
  10. atomqwerty

    Ecliptic, Celestial equator and horizon?

    Hi, I think I have I little misunderstood about these three concepts: Ecliptic Celestial equator Horizon Can someone explain me the difference between them, specially between the second and the third ones? Thank you carlos
  11. J

    Gravity at different locations on earth (poles and equator)

    Homework Statement Determine how much greater the gravitational field strength, g, is at the pole than at the equator. Assume a spherical Earth. If the actual measured difference is Δg = 52 mm/s2, explain the difference. Homework Equations g=G*m1*m2/r^2 The Attempt at a Solution...
  12. P

    Centripetal Acceleration at Equator

    Homework Statement An individual standing at the equator: a)What is this individuals centripetal acceleration caused by the Earth's rotation? b)How fast would the Earth need to spin in order for the centripetal acceleration to be equal to g? T=1 day radius of Earth = 6.4x10^6 m...
  13. Amith2006

    What is the Coriolis force at the equator?

    I was going through the concepts of Coriolis force but got stuck at the point that the Coriolis force is zero at the equator. Consider a person moving along the equator with a velocity v. Mathematically, Coriolis force= -2m(w x v) In this case though the latitude is zero...
  14. D

    If a 10km Asteroid Impacted the Pacific along the equator

    Say between Hawaii & French Polonesia. What would it look like standing on the beach in LA or Sydney? Can anyone give detailed description? Like would the sky out on the ocean front light up like a second sun? What kind of a wave? How far inland would it reach? Would it be followed by...
  15. H

    How much will it weigh at the equator?

    Homework Statement Take the Earth to be a perfect sphere of 1.274×107 m. If an object has a weight of 96.9 N while on a scale at the south pole, how much will it weigh at the equator? take the equatorial spin speed to be 465 m/s. Homework Equations No ideas. The Attempt at a...
  16. D

    Linear velocity at equator with respect to the sun

    Homework Statement What is the linear velocity of a persion standing at the Earth’s equator with respect to the Sun, when the Sun is just at the Eastern horizon? Homework Equations Not sure, I used to v=d/t to solve for a person's linear velocity at the equator, just not sure how to handle...
  17. M

    Centripetal acceleration at equator

    The centripetal acceleration of a person standing at the equator is about 0.03 m s–2. (Radius of the Earth = 6.4 × 106 m.) The size of the force R provides a measure of the apparent strength of the gravitational field. Show that the apparent field strength g at the equator differs from...
  18. M

    Tunnel from north pole to equator

    Hi all! I'm not so good at physics so i decided to turn to you. So please help me. Homework Statement I have to calculate how the object (ball) moves when droped into the tunnel (as seen in the picture), and how long the journey takes. We assume that Earth is round and there is no friction and...
  19. edpell

    Mass at equator versus mass at pole

    Has anybody ever done an experiment to measure the mass of an object at the equator and then at the pole to see if they differ due to the higher velocity at the equator? Or at least during the part of the day when the Earths rotation velocity and the Earth sun orbit velocity add up. I guess a...
  20. E

    Would one weigh more on the equator or on the North Pole?

    Hello, just wondering if you could apply Fg=mg to this. So the gravitational forces on the equator versus on the North Pole would differ and therefore, you would weigh more on the North Pole. According to what I found, the the gravitational acceleration is 9.78 m/s2 at the equator and 9.83 m/s2...
  21. B

    Calculating Escape Velocity on the Equator: Is It Possible?

    hello... I've got some small problem with Escape velocity. So... is it dependent on geographic coordinate ? I suppose "Yes!"... but is it true? Using conservation of energy, I calculate this velocity on equator this way: \frac{mv^2}{2}= \frac{GMm}{R} - \frac{m(2 \pi R)^2}{T^2*R } Am I right ?
  22. T

    Is There a Smooth Map from S^n to the Equator E of S^n for n ≥ 2?

    For n\geq 2, is there a smooth map f: S^n\rightarrow E (E is the equator of S^n) which has the property that the restriction of f to E is a diffeomorphism from E to E?
  23. I

    Why does the sun travel faster about its equator?

    Would this be valid for all other planets as well?
  24. B

    Charged particle and Earth's magnetic field at equator question

    Homework Statement Stumped on this one. A charged particle hurles through space creatings its own magnetic field, if it strikes the Earth's equator, the 2 magnetic fields interact and... a) do not affect the particles direction b) change the particles speed but not direction c)...
  25. M

    Moon's Inclination To Earth's Equator

    I'm trying to find a graph showing the cycle of the Moon's orbital inclination relative to the Earth's equatorial plane. A google search has revealed that the Moon's inclination is between 18.29° and 28.58° to the Earth's equator. But this is where the information ends. Where is the graph...
  26. P

    Calculating Weight at Earth's Equator: 600.0 N to 597.9 N

    Homework Statement Suppose the Earth is a perfect sphere with R=6370 km. if a person weighs exactly 600.0 N at the north pole how much will the person weigh at the equator? (hint: the upward push of the scale on the person is what the scale will read and is what we are calling the weight in...
  27. Shackleford

    Exploring the Equatorial Bulge: Understanding Gravity on a Rotating Sphere

    Assuming a perfect sphere, mg - w' = m (v^2/r) g' = g - (v^2/r) I understand there's a constant radial acceleration because we're not flying off the planet. Theoretically, the difference should be 0.0337 m/s^2, but isn't because the Earth "bulges" at the equator. Why is there a difference on...
  28. M

    Calculate Speed of 91.7 kg Person at Equator

    Homework Statement An early major objection to the idea that Earth is spinning on its axis was that Earth would turn so fast at the equator that people would be thrown into space. Given : radius of Earth = 6.37 × 106 m, mass of Earth = 5.98 × 1024 kg , radius of moon =...
  29. T

    Magnetic Flux, Equator and flying bullets

    Homework Statement At the equator, the earth’s magnetic field is approximately horizontal, is directed towards the north and has a value of 8 × 10^{-5} T. (i) Estimate the EMF induced between the top and bottom of a bullet shot horizontally at a target on the equator if the bullet is...
  30. V

    Angular Momentum of the earth at the equator

    Homework Statement For a 98 kg person standing at the equator, what is the magnitude of the angular momentum about Earth's center due to Earth's rotation? Assume the Earth has a radius of 6.4 x 106 m. Homework Equations Angular Momentum = rmv * sin(theta) The Attempt at a...
  31. B

    Why do pendulums swing more slowly at the equator?

    I was asked this recently and the only explanation I could come up with was that the Earth is oblate and the difference in R would account for the difference in the period. Is this wrong? Is this even a real phenomenon (the longer period at the equator than at other latitudes)?
  32. F

    Forces Acting on Person Standing at Earth's Equator

    (a) Assume that the Earth is a uniform sphere with a radius r which rotates such that the speed of the ground at the equator is v which is constant. (i) Draw a diagram showing the forces acting on a person standing on the equator. There would be the following forces acting on the person...
  33. 7

    Tangential Speed at the Equator and Beyond

    [SOLVED] Tangential Speed at the Equator and Beyond Homework Statement The Earth has a radius of 6.38 X 10^6m and turns on its axis once every 23.9 h. (a) What is the tangential speed (in m/s) of a person living in Ecuador, a country that lies on the equator? (B) At what latitude (i.e. theta)...
  34. T

    Airplane around the equator

    1. A)How fast and in what direction would an airplane need to fly(relatively close to the ground) around the equator to always stay in sunlight or darkness? B) How fast and in what direction would an airplane need to fly at 40 degrees North Latitude to always stay in sunlight or darkness?Im...
  35. M

    Gravitational Force and weight at the equator

    Homework Statement Suppose the Earth is a perfect sphere with R=6370 km. If a person weighs exactly 600.0N at the north pole, how much will the person weigh at the equator? (Hint: the upward push of the scale on the person is what the scale will read and is what we are calling the weight in...
  36. B

    Discussing the Pulsating Equator Hypothesis

    William Astley said: I found myself wondering about the pulsating equator recently. For those not in the know, Andre presented this excellent nutshell description in a previous https://www.physicsforums.com/showthread.php?t=153634&highlight=pulsting+equator". Check out this cool...
  37. H

    Weigh heavier at the equator or at the north pole?

    One quick question about forces i have. Would an appear appear to weigh heavier at the equator or at the north pole? I assume both places would have have the same weight. A little feedback would be appreciated
  38. F

    Gravitational Attraction at Equator

    The weight of a person at the equator, as determined by a spring balance, is 725N. By how much does this differ from the true force of gravitational attraction at the same point? Assume that the Earth is spherically symmetric. This question is on a section that we havn't even done yet so I...
  39. Q

    Discover the Science Behind Age Differences at the Equator vs. Poles

    Since relativity says that the faster you go, the slower time goes, then you are younger at the equator, since the equator spins faster than the poles. Therefore you are younger at the equator than at/near the poles. Am I right? Even if it is a very minute amount.
  40. A

    Calculating Speed at Equator: 91.3kg Person

    I thought I set up the equations correctly, but the speed I got seemed too fast. An early objection to the idea that the Earth is spinning on its axis was that Earth would turn so fast at the equator that people would be thrown into space. Show the error in this logic by calculating the...
  41. U

    Equator vs Pole: How Does Rotation Affect Weight?

    As the Earth is spinning, how much more would a kg of say, platinum, bought at the equator, weigh at the North pole?
  42. V

    Are there any seasons in regions along the equator ?

    Are there any seasons in regions along the equator ?
  43. C

    Circular motion at the equator

    1. An object of mass 2.00kg is i)at the Poles, ii) at the Equator. Assuming the Earth is a perfect sphere of raius 6.4 x 10^6 m, caulculate the change in weight of the mass when taken from the Poles to the equator. I solve it in this way: At the Poles, mg - R = mv^2 / r...R = mg - mv^2 /...
  44. R

    How does the Earth's rotation affect time and weight at different latitudes?

    With a speed of about 460m/s for the Earth's surface at the Equator as it spins around its axis. Using 2 Atomic Clocks tested to be accurate and match each other and both weighing exactly 100 lbs at an arctic lab site pretty much at the north pole. Moving one clock to Ecuador pretty much...
  45. G

    Finding Acceleration for Object on Equator

    An object lying on Earth's equator is accelerated in the following three directions. (a) toward the center of Earth because Earth rotates (b) toward the Sun because Earth revolves around the Sun in an almost circular orbit (c) toward the center of our galaxy because the Sun moves about the...
  46. C

    Calculate Weight Difference at Equator: 715N Gravitational Force

    The weight of a person at the equator, as determined by a spring balance is 715N. By how much does this differ from the true force of gravitational attraction at the same point? Assume that the Earth is spherically symmetric. I've tried many different forumla's but can't seem to get the...
  47. S

    Solving a Ball Dropping Problem on the Equator

    Hi! I need som hints on what method to use when solving this problem: There is a point on the ground somwhere on the equator. 100 m right above the point a ball is dropped. Where will the ball land? I'm neglecting air resistance and assuming Earths' gravitational acceleration to be...
  48. P

    Magnetic fields at earth equator

    Near the Earth's equator, the Earth's magnetic field is approximately horizontal. What current would have to flow through a long wire with a mass density of 10g/m to keep the wire floating in mid-air? What would be the direction of the wire, and the current in the wire? Well, I know I'd...
  49. G

    Launching projectile from north pole to equator

    I am trying to find what velocity and angle of launch is required for a projectile to be fired from the North pole and land somewhere on the equator. I was thinking 45 degrees with muzzle velocity 9401m/s but that sounds ridiculous. Also how much time would it be in the air for?
  50. G

    Fireing projectile from north pole to equator

    I am trying to find what velocity and angle of launch is required for a projectile to be fired from the North pole and land somewhere on the equator. I was thinking 45 degrees with muzzle velocity 9401m/s but that sounds ridiculous. Also how much time would it be in the air for?
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