Which of these is closest to the age of our solar system?
a. 0.8 million years old
b. 9.6 million years old
c. 120 million years old
d. 4.6 billion years old?

Contrast the force of gravity between these pairs of objects: 1-kg mass and a 2-kg mass that are 1 m apart; a 1-kg mass and a 2-kg mass that are 2 m apart; and two 2=kg masses that are 1 m apart. i dont understand.