Gravity
What is Gravity ?
Gravity is the force of attraction between two bodies which have mass.
Although the force of gravity can be discussed at any point in space, we will limit our discussion here to the same place we limit our flying, i.e near the planet earth.
- Within reason, near the surface of the earth the force of gravity is 9.8N kg-1
- The force of gravity is very weak, it can be overcome by a magnet picking up a paperclip.
Mathematically
- G
- Gravitational Constant = 6.67300 × 10-11 m3 kg-1 s-2
- g
- Acceleration due to gravity (on earth) = 9.807 ms-2
- M
- Mass of Earth = 5.9742 × 1024 kg
What this means
Gravity is what gives a mass its weight, on earth a brick with a mass of 1kg will weigh approximately 10N. However if we take the same brick to the moon it will weight only 1.6N due to the moons reduced gravity.
The brick still contains the same amount of matter, it just weighs less.
Web references