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Gravity
One of the four fundamental interactions, gravity is responsible for the fact that any objects with mass attract one another. According to general relativity, it is a space time curvature, but according to quantum mechanics it is the result of exchanges of virtual gravitons.
4,784 Questions
The equatorial gravity on Mars is 3.69 m/s2 or 0.376g (37% that of Earth).
If you weighed 100 lbs on Earth you would weigh 37.7 lbs on Mars
What devices depend on gravity to work?
Devices like water clocks, barometers, and some types of scales depend on gravity to function properly. For example, a water clock relies on gravity to control the flow of water through a narrow opening, while a barometer uses gravity to measure air pressure. Scales rely on the force of gravity to accurately measure the weight of an object.
Why use kerosene in the test specific gravity of cement?
Kerosene, a petroleum product will not interact chemically with Portland cement - water will.
Why should you keep a low center of gravity when lifting?
Centre of gravity is a point around which an item is perfectly balanced. If you had a hinge on that point you could turn the item any which way and when you took your hand away the item would stop in whichever position you left it in. Lowering the CoG means moving heavied bits closer to the bottom so that the CoG also ends up lower.
What are the entropy and enthalpy?
Enthalpy is the energy of the molecules. It cannot be measured, although CHANGE in enthalpy of reactions can be measured. It's simply heat energy. Exothermic reactions have anegative enthalpy change(which means energy of the products is lower than that of the reactants). Endothermic reactions have a positive value(energy of products is higher than that of the reactants). Entropy, on the other hand, is the degree of disorder. It's the measurement of how disordered a substance is. For example, particles in a solid are regularly arranged, so they are less disordered, and have a low value of entropy. Gases have much higher entropies. Entropy of an individual compound can be measured/calculated.
What is the mks unit for acceleration gravity?
The SI units are 'meter' for distance and 'second' for time.
'Acceleration' is a derived unit that uses both of them. it's [ meter/second2 ].
Is specific gravity a vector or scalar quantity?
Gravity is a force, and forces have magnitude and direction; hence, it is a vector.
Is the gravity on Venus weaker or stronger than on Earth?
The gravity on Mercury is 3.7m/s2 (metres per second squared). Compared to the gravity on Earth, at 9.8m/s2, Mercury's gravity is 37.75% of Earth's. This means you would weigh just over a third of your body weight if you were stood on the surface of Mercury - that is, assuming you find a way of surviving temperatures ranging from −180 to 430°C!
How did Issac Newtons law on gravity change the world?
Newton described Universal gravitation & the three laws of motion. As a result of his discoveries, astronomy and physics have developed immensely over time. Scientists now understand that every object in the universe has a force that attracts each other and the strength of the force depends on the size of the object. Also, Newton's Laws of Motion give people a better understanding of what is possible regarding movement. This is very beneficial, especially in mechanics and space travel. Overall, Newton had an enormous and lasting impact on science.
Newton also changed how we view light. He found that ordinary "white" light could be broken into component colors by shining the light through a prism. The prism refracted the light, producing all the colors of the rainbow -- the familiar Red, Orange, Yellow, Green, Blue, Indigo and Violet (or "Roy G Biv") we all know so well today.
How does gravity relate to a stream's ability to erode and deposit materials?
Gravity influences a stream's ability to erode materials by pulling them downstream. The force of gravity helps water to carry sediment and erode the streambed. Additionally, gravity plays a role in the deposition of materials by causing sediment to settle out of the water when the stream's velocity decreases.
Which scientist discovered gravity?
Gravity is a term coined by Sir Isaac Newton.
Newton discovered Gravity. He noticed this phenomena in the world famous story when an Apple fell down from a tree under which Newton was sitting, and Newton thought, as to why the apple fall down and not upwards or sideways. Hence leading to his discovery of Gravity.
Who discovered acceleration due to gravity?
Sir Isaac Newton was the first to postulate gravity as we know it; a force exerted by anything with mass on anything else with mass, according to the product of the masses used and inversely according to the square of the distance between them
What causes the gravitational pull between the moon and the earth?
Every 'body' in the universe is attracted - by gravity - to every other body in the universe.
Whether that attraction is noticeable depends on the relative size of the bodies and the distance between them.
The moon is attracted to the Earth because the Earth is so much larger than it - just as the Earth is attracted to the Sun, due to the size of the Sun.
Who is the founder of the law of gravity?
The current theory of gravity, General Relativity, was developed by Albert Einstein between 1905 and 1915. Before that the most advanced model was Newtonian gravity, developed by Isaac Newton.
Of course Einstein's model is identical to Newton's in the low mass limit.
What is the mass of an object that weighs 80N?
'Weight' is a measure of how heavy something is on the Earth's surface. On the Earth's surface, weight equals mass. Therefore, if a person has a mass of 80kg is on the Earth's surface, her weight is also 80kg, too.
If a mineral's specific gravity is less than 1 will it float?
Yes. That's what specific gravity is all about - the comparison of the density of a material to that of an equal volume of water. If a material or substance has a specific gravity equal to that of water, its specific gravity (sometimes called "spee gee" by the chemists) is 1. If it is more dense, say twice as dense as water, its spee gee will be 2. If the spee gee of a substance, in this case a mineral, is less than 1, it is less dense than water and will float. There may be a few exceptions for porous materials, but this is the rule.
How does distance affect the sun's gravity on planets and other objects in the solar system?
To some degree, it will decide it's surface temperature. That is, the closer to the sun, the hotter the planet will be. But this is not always the case, for example, Venus is hotter than the Earth not solely because it is closer to the sun, but because of the heavy gaseous atmosphere that traps the heat of the sun.
note: distance needs to be in meters, mass in kg
g = (G*Mass Earth)/(Radius earth + distance above earth surface)^2
g = (6.673e-11 * 5.98e24)/(6.38e6 + 12800e3)^2
g = 1.08 m/s^2
force = mass * acceleration
force = 1200 kg * 1.08 m/s^2
force = 1296 N
Also, there is an easier formula.
Earth's gravitational force decreases with the square of the distance from earth's center. So, The force of gravity = (1/r^2)mg
Force of gravity = (1/3^2)(1200)(9.80m/s/s)
r = 3 because the craft is 2 Earth radii away from the surface and we need to calculate to Earth's center
F = (1200 * 9.8m/s/s)/9 = 1300N rounded to 2 sig figs
What would happen if you fell into the center of the earth and there was no gravity?
There would be no net gravitational force at the center of the Earth (due to the Earth alone), if the Earth were perfectly spherical and made up "shells" of material of uniform density.
In fact, the "real" Earth is pretty close to those "ideal" requirements.
You can use the "related link" below, to confirm these details.
Of course, actually reaching the Earth's center is impossible with present technology. We haven't even drilled very far down yet.
Molten lava could disintegrate you long before you ever reached the center.
In fact, the center of the Earth is reckoned to be at about the same temperature as the surface of the Sun!
Also, there are huge pressures inside the Earth.
Another answer:
Imagine a hole that is drilled straight through the center of the earth from one side to the other. This hole is big enough to jump into. I jump in *crazy thing to do*; at that point I am falling.
As I approach the center of the earth, the question is, do the gravitational forces increase, or do they cancel.
If gravity increases, than I have the potential of exceeding my muscular-skeletal capacity to sustain me. (Try to forget the molten core for just a few minutes.)
If gravity cancels, than I have the potential of hanging around for quite sometime.
Through observation, we know that as an object goes further from the Earth, it feels less of Earth's gravity. If it goes far enough away from the Earth, it will not be affected by Earth's gravity. As objects get closer to Earth, gravity increases. But in all of those observations, the mass of the whole planet has always been to one side of the object that is being attracted. For example, when a plane is in flight, the mass of the whole planet is pulling the plane downward.
I do not know of any observational models that clearly demonstrate the concept of a larger mass (one with appreciable gravity) surrounding a smaller mass (one with negligible gravity). I would suggest, however, that since mass is directly proportional to gravitational attraction, and, at the center of the earth all of the mass is outward, toward the surface in all directions, that if I were in the center of the earth, I would be attracted outward, evenly in all directions. It would feel as if I were in a non gravity environment.
Hypothesis: In the center of the earth, gravitation forces, acting evenly outward in all directions, create a limited spherical zone where gravity is canceled.
So I believe the first answer is right.
Questions not figured into this hypothesis include: In the canceled gravity zone would I become aware of the effects of the Moon's gravity, or the gravity of the Sun?
NOTE on celestial body gravity. Their effects would be there, but about on the same order that astronauts feel when they are in orbit. Not enough for human senses to really pick up. While in orbit, you technically experience microgravity, not zero gravity.
Take the example of drilling a hole all the way through the Earth (ignoring the molten outer core and other problems).
You would indeed encounter effectively zero gravity at the center of the Earth.
I say effectively, because people are not points - so there would be microgravity effects that are felt most at your extremities.
An object dropped into that theoretical hole drilled through the Earth would accelerate towards the center of the Earth.
At the center of the Earth its speed would reach its maximum.
The object would continue to move, but would start getting slowed by the increasing net gravity pulling it back towards the center.
The object should just reach the surface on the other side of the Earth, ignoring frictional forces and other complications. Then it would start to fall again.
But even barring lava, I doubt you'd survive in a hole drilled through. And this is because the air pressure would crush you. The net effective force of gravity at the center is zero, but that air column will have a lot of pressure, most of that air is not at the center, is encountering the effects of gravity and is crushing you.
A second note on a person not being a point: If your center of mass was positioned exactly on the center of mass for the Earth, you would actually encounter a slight gravitational force PULLING you apart. I suspect it would be negligible and no more noticeable than the Sun's pull. If someone wants to do the integral calculus for a human shape in a sphere we could figure out the effective gravitational pull.
Yes, Mecca is "centre" of Earth. It is scientifically proved.
It is not scientifically proven yet, but the Muslims believe that Mecca should be the centre of the Earth!
Another Answer: The centre of the Earth is a very hot place and is under very high pressure. You wouldn't like to be there. It is about 4000 miles below the surface.
Does the gravity on earth affect other planets?
Almost certainly - amongst other aspects, gravitational disturbances caused by stars passing close to the solar system has been suggested as the cause for increased meteor impacts on the Earth (look up the theoretical star 'nemesis' on wikipedia for one rather speculative theory in this vein)
What is the difference between ideal and practical pendulum?
An Ideal pendulum is ones that would be the first choice if you could choose all the materials (ideal materials). A practical pendulum is one that is readily available and reliable (made from things you have right now and are available to use).
Is there gravity at the equator?
we know g equalls GM/R*R. Therefore g is inversly proportional to R spuare. Where R is radius of the planet. The R at the equator is the greatest. Hence the value of g is min at the equator. The value if g increases from the equator to the poles.
What is the relationship between gravity and friction?
Gravity and friction is different because gravity is the force of something thats going downward and friction is the force that is being pushed if touching the ground. For example, if you was to go skating the friction is the force that you applied between the skates and the ground.
What were Isaac newton's discoveries in gravity?
Even before Sir Isaac Newton was born, roughly 16 out of every 19 people had already noticed that when they jumped out of bed, their feet went to the floor, and that when they dropped something, it fell to the ground. Gravity was already quite universally known, whether or not that's what anybody called it, and it didn't need to be discovered.
All Newton did was to accurately describe how it works.
Furthermore, he took the INCREDIBLE leap of stating that the gravity we experience on our Earth also influenced the motions of planets around our Sun.
How does gravity affect cycling?
Towards the center of the Earth. Really. Down, basically. If you're trying to go uphill, you'll get pulled backwards. If you're going downhill, you'll get pulled forwards, because of the slope of the hill and the action of the wheels.
