Gravity

What is gravity? This is the attraction between two masses. Isaac Newton came up with the Universal Law of Gravitation: All masses are attracted to one another. The extent of the attraction depends on: The mass of the two objects The distance that separates them.

Gravity The greater the mass of the objects, the stronger the attraction is. The farther apart the objects are, the weaker the attraction is.

Do objects fall at a constant speed, or do they get faster as they fall? Objects pick up speed due to gravity as they fall. This is called acceleration. The acceleration caused by Earth’s gravity is 9.8 m/s2 https://www.youtube.com/watch?v=WN_DsPz8wnI

Different gravitational accelerations: Moon (1.6 m/s2) Mars (3.7 m/s2) Jupiter (24.8 m/s2)

Gravity keeps the planets going around the sun The planets of the solar system are kept in orbit (an elliptical path around the sun) by gravity. Which planet experiences the most gravitational attraction to the sun, and why? Which planet experiences the least gravitational attraction to the sun, and why?

Are you gravitationally attracted to the person next to you?

Are you gravitationally attracted to the person next to you? Yes!

Are you gravitationally attracted to the person next to you? Yes! 0.00000017 N

In summary Everything on Earth falls at the same acceleration. This means that all dropped objects should hit the ground at the same time. We only notice differences due to the resistance of air.

Question to think about… What happens if you drop a penny from a very tall building? Would it accelerate so fast that it could cause serious injury or death?

https://www.youtube.com/watch?v=PHxvMLoKRWg

No! Eventually, falling objects reach a maximum speed and stop accelerating due to the resistance of air. This maximum falling speed is called terminal velocity.

Are mass and weight the same thing?

Are mass and weight the same thing? NO! Mass is the amount of matter an object possesses, while weight is a force exerted by gravity on a mass.