Which of these was a contribution of Newton to astronomy? A) ...

[tsand2]

Which of these was a contribution of Newton to astronomy?
 
  A) Artificial satellites could be put into orbit about the Earth.
  B) The Sun's gravity is greatest on a planet at perihelion, so the planet must speed up.
  C) The Moon pulls as strongly on us as we do on it.
  D) His differential calculus lets us calculate planetary motions more accurately.
  E) All of these were due to Newton's work.

Question 2

The angular size of an object depends on which two quantities?
 
  A) The object's actual size and its mass
  B) The object's distance from us and its brightness
  C) The object's actual size and its distance from us
  D) The object's brightness and its mass

[bookworm410]

Answer to Question 1

E

Answer to Question 2

C

[tsand2]

Gracias!

[essyface1]

Excellent