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​GRAVITATIONAL FORCE

Gravitation is a natural phenomenon by which all objects with mass attract each other. In everyday life, gravitation is most familiar as the agency that endows objects with weight. Gravitation is responsible for keeping the Earth and the other planets in their orbits around the Sun; and much more.

Newton's Law of Gravitation

  • Three things you need to remember about Gravitational Constant
  1. UNIVERSAL - This means that this number is the same wherever you are in the universe.​
  2. SMALL- The number is to the negative eleventh 
  3. SAME ALL THE TIME- The number never changes. ​

The force of gravity depend on:​

  • MASS of the two objects
  • RADIUS or distance between the two objects
  • GRAVITATIONAL CONSTANT (G) a number same throughout the universe
  • G = 6.67 x 10^ -11 Nm^2/ kg^2 
  • Remember that (G) or Gravitational Constant is different form (g) gravity !! 

In this equation, the force of gravity equals the Gravitational Constant times the mass of object one and object two divided by the radius squared.  There are things you need to keep in mind when solving and plugging in the information into this equation. Keep in mind that the smaller radius equals a bigger force, and the bigger the radius the smaller the force. Why is this you ask? Well part of  it has to do with Newton's 2nd law of being proportional or inversely proportional. Since the mass is proportional to force, the bigger the mass, the bigger the force.But  the equation includes inversely squared with radius squared. For example, say the radius was 5  When you square that number it equals 25. But since the equation is inversely squared  the force is 1/25. To explain in more simpler terms, the farther the distance the weaker the force. Now do you understand? .... Good.

NOW SOME REVIEW

What is larger the force the earth exerts on you or the force you exert on the earth?

I don't see how they can be anything BUT equal. The force being talked about is obviously gravity- an attractive force between two objects. Every particle of my body attracts every particle of the earth. It wouldn't be stated any differently from the earth's point of view.

How and when are F=ma and f=gm1m2/r2 equal to each other?

When you are comparing an object to the force of Earth.

Scales

Scales is the measuring of gravitational force between you ( or object ) and the Earth.When we step onto a scale, we're acting on the Earth an amount of force, measured in newtons, and in return the Earth is pushing back up on us with the same amount of force. So  when we step up on to the balance, we see the force that we are putting on the Earth, and what the Earth is putting back on us.

Misconception

The Earth's gravitational pull is greater than the moon's gravitational force right? Wrong. The Earth and the moon exert the same force of gravity on each other, even though the earth has a bigger mass than the moon. This is proved in newton's 3rd law that states whenever one object exerts a force on a second object, the second object exerts an equal( in magnitude) and opposite(in direction) force on the first object.   In other words, the moon pulls on the Earth with the same force that the Earth pulls on the moon.

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