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### Course: Middle school physics - NGSS>Unit 2

Lesson 1: Gravitational forces

# Gravitational forces

Review your understanding of gravitational forces in this free article aligned to NGSS standards.

## Key points:

• The force of gravity, or gravitational force, pulls objects with mass toward each other.
• We often think about the force of gravity from Earth. This force is what keeps your body on the ground.
• But any object with mass exerts a gravitational force on all other objects with mass. For example, there is a gravitational force between you and every object around you!
• The gravitational force between two objects is larger when the masses of the objects are larger. That’s why you can feel the gravitational force between you and Earth, but the force between you and objects with smaller masses is too weak to feel.
• The gravitational force between two objects also depends on the distance between their centers. The further objects are from one another, the weaker the force is.

## Want to join the conversation?

• I wonder what happens if you stand very close to the Earth's core. (If you can't burn to the heat)
• huh good question I am wondering that too
• wait, so we can defy all rules of gravity by just picking something up. That's epic.
• Haha. Not excactly. Gravity is still acting on the object when you pick it up, but the force you apply to pick the object up is greater then the gravitational pull so you can't tell.

Hope this helps!
• I wonder what happens if 2 items with difference gravitational touches for ex. 2 magnets on opposite sides - and +
• they would pull together
• I wonder what would happen if I moved the Earth out of its orbit and into a straight line.
• we'd die
• What if I stay in space for 1 week I'll be dead?
• you will die after the first 90 seconds and thne youll freeze as a whole unless youre next to a star then youll burn to a crisp peice of toast:)
• what if you had a balloon? Why does it float not bang straight to the ground?
• Helium! It's less dense than air, and balloons that float are typically filled with helium, a gas that is less dense than the gasses in earth's atmosphere. That means a balloon-sized ball of helium weighs less than a balloon-sized ball of air. The difference in density is the key to a balloon`s floatation.

I hope this helps!
• what is the difference between gravity and gravitational force?
• Gravity is the name of the phenomenon and gravitational force is how much power the gravity of an object has.