PROJECTILES, SATELLITES AND GRAVITY

Satellite and Circular Motion

Free Fall Motion

http://www.youtube.com/watch?v=nnwmK2Xa5FI 2.5 min on moonhttp://www.youtube.com/watch?v=efzYblYVUFk

http://www.youtube.com/watch?v=7ciStUEZK-Y falling on the moon

http://www.youtube.com/watch?v=8V9quPcNWZESinging on the moon

http://www.youtube.com/watch?v=VIBgVnlXE5UDriving on the moon

http://www.youtube.com/watch?v=f-FxhCZold0Golf ball on moon

http://www.youtube.com/watch?v=2V9h42yspboVomit comet

http://www.youtube.com/watch?v=gTqLQO3L4KoWater balloon in vomit comet

http://www.youtube.com/watch?v=KFPvdNbftOYWashrag in space

http://www.youtube.com/watch?v=o6nhTeLO5yYFive senses: smell in space

http://www.youtube.com/watch?v=qHrBhgwq__QKnitting needle electric force field

GRAVITY The force of attraction between any two

objects with mass. A field force (a non-contact force) A universal force (Gravity is

everywhere) The weakest of the 4 fundamental

forces

In orbit around the Earth, Astronauts experience 90% of the gravitational force you experience at the Earth’s Surface

Gravitational Force Field

Einstein’s View of Gravitymass deforms the space-time fabric, Earth follows the contour (even light follows the contours of space-time)

Gravity Fg is the force of gravity and your

weight All objects with mass are

surrounded by a gravitational force field

Gravity

Gravity depends upon the mass of the objects and the distance between them

M1

M2

d

More mass, more gravity

M1

M2

d

Increase distance, decrease gravity

Inverse-Square Law Changes in the intensity of gravity are

caused by changes in the mass or in the distance between masses, and follow the inverse-square law.

Electrical and magnetic fields, light, radiation, sound, gravity, and even spray paint.

Systematic decrease in concentration or intensity due to spreading out.

  Intensity = 1

d2

Law of Universal Gravitation Newton’s law of gravity Fg = m1 x m2 x G

d2

G is the gravitational constant 6.673 x 10-11 N x m2/kg2

Can be used to calculate the gravitational force between any two objects

Universal Law of Gravitation Gravity depends upon  --Mass --Distance between masses Differences in the intensity of gravity

can be calculated using Newton’s Universal Law of Gravitation 

G is the gravitational constant G = 6.672 × 10-11 m3 /(kg sec2). Measure distance from center of object.

F = G m1m2

d2