Description: Gravity is strong on Earth because the mass of the Earth is so large. 
Key Terms: Mass, Earth, distance, radius, algebra, acceleration

Description: Video comparing the free fall of a bowling ball and a feather when there is air resistance and when the air has been removed. 
Key Terms: Gravitational force, moon, air resistance

Description: Review of measuring speed, net force, and the constant acceleration of free fall. 
Key Terms: Gravitational force, speedometer, net force, constant speed, constant acceleration