The average value of g is 9. To convert a mass in kg to a force in Newtons multiply by 9. Now you know how to deal with gravity here on Earth just multiply mass by 9. Well, mass and energy make space curved or distorted , so it is natural for objects to follow a path towards each other. Here an object naturally follows space-time towards Earth. Actually needs lots more particles!
But we normally simplify it by imagining each ball's mass and energy is at its center, called the Center of Gravity. They are very slightly only 9 millionths of a Newton attracted towards each other! From the center of the apple to the center of the Earth is km 6. And of course, the value of g will change as an object is moved further from Earth's center.
For instance, if an object were moved to a location that is two earth-radii from the center of the earth - that is, two times 6.
As shown below, at twice the distance from the center of the earth, the value of g becomes 2. The table below shows the value of g at various locations from Earth's center. Distance from Earth's center m. As is evident from both the equation and the table above, the value of g varies inversely with the distance from the center of the earth.
In fact, the variation in g with distance follows an inverse square law where g is inversely proportional to the distance from earth's center. This inverse square relationship means that as the distance is doubled, the value of g decreases by a factor of 4. As the distance is tripled, the value of g decreases by a factor of 9. And so on. This inverse square relationship is depicted in the graphic at the right. The same equation used to determine the value of g on Earth' surface can also be used to determine the acceleration of gravity on the surface of other planets.
The value of g on any other planet can be calculated from the mass of the planet and the radius of the planet. The equation takes the following form:. Using this equation, the following acceleration of gravity values can be calculated for the various planets.
The acceleration of gravity of an object is a measurable quantity. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them:. If the bodies in question have spatial extent rather than being theoretical point masses , then the gravitational force between them is calculated by summing the contributions of the notional point masses which constitute the bodies.
As a consequence, for example, within a shell of uniform thickness and density there is no net gravitational acceleration anywhere within the hollow sphere.
Furthermore, inside a uniform sphere the gravity increases linearly with the distance from the center; the increase due to the additional mass is 1. Gravitational Field of Earth : Diagram of the gravitational field strength within the Earth. Privacy Policy. Skip to main content. Uniform Circular Motion and Gravitation. Search for:. The Law of Universal Gravitation Objects with mass feel an attractive force that is proportional to their masses and inversely proportional to the square of the distance.
Gravitational Attraction of Spherical Bodies: A Uniform Sphere The Shell Theorem states that a spherically symmetric object affects other objects as if all of its mass were concentrated at its center. Learning Objectives Formulate the Shell Theorem for spherically symmetric objects. The gravitational force on an object within a hollow spherical shell is zero.
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