An object with twice as much mass will exert twice as much gravitational pull on other objects. Thegravitational force increases as the size of an object increases. On the other hand, the strength of gravityis inversely related to the square of the distance between two objects.
Comma is used incorrectly in the sentence <em>The Great Hall is open to the public, you must reserve a spot in advance </em>because it attempts to join two independent clauses. Instead of a comma, you should use a semi colon here.
