Chapter 5

You are sitting next to a person who has twice as much weight. You get up and move one seat over, doubling your distance from them. Did the gravitational force between you increase, decrease, or stay the same?

1/d^2, so the gravitational force decreased by 1/4

Compared to the strength of Earth's gravity at its surface r=Re where Re is the radius of Earth, how much weaker is gravity at a distance of r = 10Re? At r = 20Re?

10Re=100 times weaker (1/(10)^2) 20Re=400 times weaker (1/(20)^2)

Why can't a spacecraft go "beyond Earth's gravity"?

It's impossible to escape the gravity of Earth due to the interaction of gravity between the Earth and the Moon

What is the difference between mass and weight?

Mass is a measure of the amount of matter in something and weight is the force exerted by the gravity on an object

What is the difference between speed and velocity?

Speed is the distance traveled by and object and velocity is the distance traveled by an object per unit in time in a particular direction