Physics gravity

G=

6.67x10^-11

How far away would one have to travel from the earth to experience no gravitational effects?

According to newtons law of universal gravitation, an object of mass will experience a gravitational attraction to earth no matter where the object is in the universe. However after a particular distance from earth the force would be too small to notice. (The distance is equal to 9 earth radii away from surface)

Keplers 2nd law of planetary motikn

An imaginary like from the sun to a planet sweeps out equal areas in equal time intervals. Planets move faster when closest to the sun and slowest when farthest away from sun (Went against churches belief that the earth is stationary and proposed the idea that planets travel at varying speeds)

Inverse square law(Newton)-

Any law that states one variable is inversely proportional to the square of another variable Can be: d, V, Fw, m

Kepler

Astronomer who used geometry and mathematics with a sun centered solar system to calculate the motion of the planets, he developed 3 laws to describe behavior of every planet satellite

Why do seasons occur?

Because earth is tilted on an axis at about a 23 degree angle and on one side of the sun the Southern Hemisphere is exposed to more sunlight and on the other side of the sun the northern hemisphere is exposed to more sunlight so the tilt of the earth causes the seasons

Why do objects fall?

Because everything on earth is attracted to earth because of gravitational attraction between objects of mass. Therefore the earth and the apple that falls are both attracted to each-other but the apple falls down more towards the earth because the earth has a much greater mass and more inertia than the apple.

Objects in orbit always falling toward the object they are orbiting

Because of Newton's first law they want to continue in a straight line but then attraction from the earth makes them fall towards the earth

Apparent weightlessness

Experiencing the effects of zero gravity due to the lack of a support force

Law of universal gravitation (Newton)

For any pair of objects, each object attracts the other with a force directly proportional to the product of the masses of the object, and inversely proportional to the square of the distance between their centers F=G(mm/d^2)

Support force

Force that balances the weight of an object at rest (normal force, tension eat)

What is the law if universal gravitation?

Gravity, as stated by newton, is a force that attracts every particle of mass to every other particle of nass in the entire universe. That means that a person here in earth is attracted to every other person object planet and star throughout the universe. Howerver the reason why we dont gravitate toward these objects is that the gravitational force between earth and ourselves js nuch stronger than any gravitatuinal force between other people buildings distant planets or stars.

Kepler- kinematics

How planets move

What factors determine the gravitational attraction between two objects?

Mass: greater the mass, the greater the gravitational force between them Distance: greater the distance between two masses, the less gravitational pull.

Cavendish

Measured the G value by using a devise with two large lead spheres and measured the attraction between them by measuring how much the rod moved ever so slightly

Cavendish

Measured the value of G

Can force of attraction =0

No because to be zero either G it one of the masses must be 0, and G is a constant and mass is never 0 so the attractive force can never be zero

Can we ever experience true weightlessness?

No, because Fw, and g are never 0 so F is never 0 so no such thing as true weightlessness

Can g be undefined

No, because for G to be undefined d would have to equal 0 and distance is never 0

Can g=0

Since F is never 0 g cannot be 0

Epicycles

Smaller circular path followed along a larger circular path, used to explain motion of the solar system to prove that earth was the center of the universe

Keplers 1st law of planetary motion

The path of the planets are ellipses with the center of the sun at one focus (Went against churches belief that planets followed circular paths)

Keplers 3rd law of planetary motion

The ratio of the square of any two planets revolving about the sun is equal to the ratio of the cubes of their average distance from the sun.

Tycho Brahe

Was the teacher of kelper, kelper used his work to help create his laws

Newton- dynamics

Why planets move the way they do