Physics 007 Quiz 1/Hw 1

Size of Local Group

5 millions light years

How far is it to andromeda galaxy

2.5 millions light years

Parsec

1 AU subtends an angle of 1 arc second

Parsec Size

3.26 light years

arc second

1/3600 of a degree

Thales

First natural explanation of the universe

Anaximander

Earth floats unsupported at the center

Philolaus

earth is not at the center

Virgo supercluster size

200 million light years

Distance between super clusters

400 million light years

Aristarchus

First heliocentric model

Anaximanders Model - Falsify

retrograde motion of plants cannot be explained by simple circular earth centered models

Philolaus Model Falsified

counter earth is not observed and planetary motions do not match predictions

How did aristarchus determine that sun>earth

Used geometry of moon phases

How much bigger is sun radius vs earth

109x

Newtons law of gravity

all masses attract each other with a force proportional to their masses and inversely proportional to the square of the distance between them

Newtons gravity law - falsified

Doesn’t explain the precession of mercurys orbit

Newtons gravity law - valid

for weak gravitational fields and low speeds

Weight - 110lbs. What would it be if earth compressed to 1/3 radius and same mass

9× - 990lbs

earths gravity

1/r²

Earths Mass → 3x at 110lbs body weight

330 lbs

Precession of perihelion

slow rotation of planets orbit over time

Precession of perihelion when only one planet orbits the sun

no precession

Newton + Einstein Theory of physics about gravitational mass of astronaut on earth is m0.

mass remains same according to both but weight changes because of gravity’s strength