# Use the law of universal gravitation to describe relationship between you and your desk

### Newton's Universal Law of Gravity ( Read ) | Physics | CK Foundation

How Gravitational Laws Affect Your Love Life Newton's Law of Universal Gravitation states: reason you don't fly off the Earth as it rotates at 1, mph— Earth has way more massive than a desk chair. You can literally quantify who has more “relationship mass” with just a few simple observations. Learn vocabulary, terms, and more with flashcards, games, and other study Key Idea: What force keeps you from falling through your bed when you lie Key Idea: Use the law of universal gravitation to describe the relationship between you and your desk. I am attracted to my desk and we are both attracted to Earths core. Basics of gravity and the Law of Universal Gravitation. Newton's law of gravitation . Here.

## Gravity and Gravitation - Newtonian Gravity

If the mass of both of the objects is doubled, then the force of gravity between them is quadrupled; and so on. Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces.

So as two objects are separated from each other, the force of gravitational attraction between them also decreases.

If the separation distance between two objects is doubled increased by a factor of 2then the force of gravitational attraction is decreased by a factor of 4 2 raised to the second power. If the separation distance between any two objects is tripled increased by a factor of 3then the force of gravitational attraction is decreased by a factor of 9 3 raised to the second power. Thinking Proportionally About Newton's Equation The proportionalities expressed by Newton's universal law of gravitation are represented graphically by the following illustration.

Observe how the force of gravity is directly proportional to the product of the two masses and inversely proportional to the square of the distance of separation. Another means of representing the proportionalities is to express the relationships in the form of an equation using a constant of proportionality. This equation is shown below. The constant of proportionality G in the above equation is known as the universal gravitation constant. The precise value of G was determined experimentally by Henry Cavendish in the century after Newton's death.

This experiment will be discussed later in Lesson 3.

Using Newton's Gravitation Equation to Solve Problems Knowing the value of G allows us to calculate the force of gravitational attraction between any two objects of known mass and known separation distance. As a first example, consider the following problem. The solution of the problem involves substituting known values of G 6. The solution is as follows: This would place the student a distance of 6. Two general conceptual comments can be made about the results of the two sample calculations above.

First, observe that the force of gravity acting upon the student a.

This illustrates the inverse relationship between separation distance and the force of gravity or in this case, the weight of the student.

The student weighs less at the higher altitude. However, a mere change of 40 feet further from the center of the Earth is virtually negligible. A distance of 40 feet from the earth's surface to a high altitude airplane is not very far when compared to a distance of 6. This alteration of distance is like a drop in a bucket when compared to the large radius of the Earth.

Newton also explained how bodies respond to forces including gravitational forces that act on them. His Second Law of Motion states that a net force i. The amount of this acceleration is inversely proportional to the mass of the object.

## Newton's law of gravitation review

This means that under the influence of a given force, more massive objects accelerate more slowly than less massive objects. Alternatively, to experience the same acceleration, more massive objects require more force. Consider the gravitational force exerted by the Earth on two rocks, the first with a mass of 2 lb 1 kg and a second with a mass of 22 lb 10 kg.

Since the mass of the second is 10 times the mass of the first, the gravitational force on the second will be 10 times the force on the first.

But a lb kg mass requires 10 times more force to accelerate it, so both masses accelerate Earthward at the same rate. Ignoring the Earth's acceleration toward the rocks which is extremely smallit follows that equal falling rates for small objects are a natural consequence of Newton's law of gravity and second law of motion.

What if one throws a ball horizontally?

### Newton's law of gravitation review (article) | Khan Academy

If one throws it slowly, it will hit the ground a short distance away. If one throw sit faster, it will land farther. Since the Earth is round, the Earth will curve slightly away from the ball before it lands; the farther the throw, the greater the amount of curve.

The ball would never get any closer to the ground, and would be in orbit around the Earth.