Gravity
Published on Nov 18, 2015
My presentation on gravity
MORE DECKS TO EXPLORE
PRESENTATION OUTLINE
GRAVITY IN GENERAL
- Gravity is the natural phenomenon where all obects are attracted to each other.
- Gravity is the weakest of the four basic forces in the universe.
- Galileo was the first to demonstrate that gravity caused the same acceleration in all objects on Earth.
- Sir Isaac Newton discovered the inverse square law of gravitation in 1687
- Albert Eistein described gravity better in his theory of general relativity in 1915
GRAVITATIONAL PULL
- Every object has a gravitational pull on other objects.
- The size of that pull is dependant on the mass of the two objects.
- Gravitation between two people is equal to the weight of a piece of paper.
- The Earth is large so its gravitational pull is strong hence objects fall to the ground
- Objects have to be very close together for the gravitational pull to be strong
ORBITS
- The gravitational pull of a planet allows smaller objects to orbit it.
- For an object to orbit it has to travel at the correct orbital velocity.
- If its velocity is too low gravity will pull it into the planet and crash
- If its velocity is too high it will break free of gravity and fly into space
- With the correct velocity the object keeps missing the planet as it falls
GRAVITY AND THE SOLAR SYSTEM
- Gravitational pull keeps our solar system together
- The sun has 99.9% of the mass of the solar system
- Hence the sun is in the centre and all the planets orbit the sun
- Similarly most plants have small moons orbiting them
- The moon's gravity can affect the planet, e.g. Tides on Earth
