Gravity What is it? Gravity is……

Gravity …. ..is a force pulling on an object Sun’s force pulling on planets to keep them in orbit Earth’s force pulling on the moon Attracts all objects toward each other

Sir Isaac Newton discovered that every object in the universe attracts every other object Force of gravity is measured in Newtons because of this discovery The strength of force of gravity depends on: Mass of objects Distance between objects

Vocabulary Mass Weight Inertia Amount of matter in an object Mass does NOT change Weight Force of gravity on an object DOES change depending on location Ex) you would weigh 1/6 of your Earth weight on the moon. This is because the moon is far less massive than Earth so the pull from the moon is less than Earth. Inertia Object in motion stays in motion until a force is acted on it

Gravity and Distance…what’s the relationship? Strength of gravity depends on distance between 2 objects as well as their masses Force of gravity decreases as distance increases. They are disproportional! Ex) If distance DOUBLES, the gravity will be ¼ of its original value

Application of skills-- What would increase the force of gravity between 2 objects? Decrease the distance or increase the mass What would decrease the force of gravity between 2 object? Increase the distance or decrease the mass

Gravity (visuals) Gravity attracts all things together. 2 M 2 M

Increase in mass=increase in force

Increase in distance=decrease in force 2 M 2 M

Inertia and Gravity…. INERTIA *the greater the mass of an object=greater the inertia *the more inertia an object has, the more force is needed to stop it *Without gravity, inertia would allow Earth to move away from the sun and the moon to move away from Earth in a straight line. *Inertia and gravity keeps the Earth from crashing into the sun *Inertia and gravity keeps the Moon from crashing into Earth *Newton’s 1st Law of Motion *an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless another force acts on it. *car analogy

Food for Thought….Exit Slip! Would the gravitational force be slightly greater if you were standing on land at sea level OR at the top of Mt. Kilimanjaro? Why?