ASTRO 1500 Quiz 2 - January 31, 2025

Which one of these was introduced to "fix" the geocentric model?

• Epicycles

• The Ellipse

• Mars

• Moons

Answer explanation

Epicycles were introduced to account for retrograde motion, which couldn't be explained otherwise with the geocentric model

Which one of these answers is NOT one of the four fundamental forces?

• Gravity

• Strong Nuclear Force

• Friction Force

• Electro Magnetism

Answer explanation

Friction is not one of the four fundamental forces, the weak nuclear force is the fourth, see slide 4 from lecture 3.

Which one of these is NOT one of Kepler's Laws

• Planets orbit the sun in an ellipse

• The period of a planet squared is proportional to the length of its semi-major axis cubed

• A planet will move faster as its orbit gets closer to the sun

• A bowling ball and feather will fall at the same speed in a vacuum

Answer explanation

While true, gravity acting at the same speed was not outlined in Kepler's Law, and is derived from Newton's Laws instead.

What is light?

• Gravitational Waves

• Fluctuations in the Aether

• Electromagnetic Waves

• An illusion created by the brain

Answer explanation

Light is the propagation of electromagnetic waves. The particle that carries this force is the photon.

Planets move in a shape called an...

• Ellipse

• Circle

• Oval

• Square

Answer explanation

Planets move in ellipses, a la Kepler's first law.

If you move twice as far away from a planet, the gravitational force of the planet on you is now __ times lower.

• 2

• 4

• 8

• 16

Answer explanation

F=GMm/r^2. So if r doubles, F will decrease by r^2. r=2 so 2^2 =4.

Tags

CCSS.7.RP.A.3

Which one weighs more?

• 1 proton

• 1 electron

Answer explanation

1 proton weighs the same as ~1800 electrons

How did the Copernican Revolution change the way people think about science?

• They believed the Heliocentric Model

• People used observations to learn about the Universe

• They only trusted divine revolution

• They stopped believing the Geocentric model

Answer explanation

The Copernican Revolution marked a change where people stopped relying on divine revelation for answer about how the Universe worked

According to Kepler's 3rd law, P^2= ...

• a

• a^2

• a^3

• a^4

Answer explanation

Kepler's third law is P^2 = a^3

Tags

CCSS.8.EE.A.2

Light at a wavelength of 400 nm would appear to us as...

• Blue

• Green

• Yellow

• Red

Answer explanation

Visible light has a range of 400-700 nm, closer the wavelength is to 400 nm the "bluer" it is and vice versa