# 22. What does it mean for a force to act in accordance with an inverse square law?

The square of the force is inversely proportional to the distance.

The force decreases if the distance increases.

The force is directly proportional to 1/r2 where r is the distance.

The force is directly proportional to the distance squared.

Question 23. 23. It takes 82 years for Uranus to circle the sun once. Approximately how far is Uranus from the sun in AU, where 1 AU is the distance of Earth from the sun?

740 AU

19 AU

82 AU

6,700 AU

Question 24. 24. Why would an observer out in space see the earth orbiting the sun rather than the sun orbiting the earth?

The sun has much more mass than the earth.

The sun's gravity pulls on the earth, rather than the earth's gravity pulling on the sun.

The same force that pulls an apple to the earth pulls the earth toward the sun.

The force of gravity decreases with distance.

Question 25. 25. What is the magnitude of the earth's gravitational field at sea level?

6.67 × 1011 N/kg

4.9 N/kg

1.0 N/kg

9.8 N/kg