Physics 20 Gravity

Front 1

gravitational forces

Back 1

attractive forces between all objects with mass

Front 2

electromagnetic forces

Back 2

result of electric charges of particles

Front 3

strong nuclear forces

Back 3

hold particles in nucleus together

Front 4

weak forces

Back 4

involves radioactive decay of nuclei

Front 5

universal law of gravitation

Back 5

proposed by Isaac Newton
- two objects with mass exert a force on each other that is always attractive
- force is very small, and only becomes significant when the mass of one or both of the objects is large

Front 6

relationships of the universal law of gravitation

Back 6

- force of gravity is directly proportional to the product of the masses objects (Fg α m1m2)
- force of gravity is inversely proportional to the square of the distances between the objects (Fg α 1/R2)

Front 7

universal gravitation equation

Back 7

Fg = Gm1m2/R2

Front 8

field

Back 8

sphere of influence - can be scalar or vector
used to describe forces acting between objects that are not in contact
when vector;
magnitude; mass of the object
direction; always towards the object

Front 9

gravitational field strength

Back 9

- symbolized by "g'
- the amount of force per unit of mass (g = Fg/m)
- measure in m/s2

Front 10

What are "g's"?

Back 10

1 g - normal acceleration that you feel acting on you due to gravity
2 g - the acceleration is twice that of the earths acceleration rate acting on you
positive g's -when force acting on you in a direction that causes blood to move to your feet. (can handle 9g's)
negative g's" - when force makes blood rush to your head (can handle -2g's)

Front 11

terminal velocity

Back 11

occurs when an object reaches constant velocity because the force of air friction upwards equals the force of gravity downwards.
Changes depending on the object. Fg + Ff = 0N

Front 12

true weight

Back 12

the weight you calculate for an objecting using...

Fg = mg
Fg = Gm1m2/R2

Front 13

apparent weight

Back 13

the magnitude of the normal force applied to an object by another object in the system

apparent weight = -Fapp = -Fn

Front 14

Einstein's Theory of Gravity

Back 14

- suggested that objects with mass distort the space that they occupy
- the greater the mass of an object, the more it bends or curves the space around it
- other objects travelling through that distorted space follow the distortions created