ASTR 100 Lecture Notes - Lecture 9: Apollo 15, Net Force

• School: University of Maryland
• Department: Astronomy
• Course: ASTR 100
• Professor: Sylvain Veilleux

Document Summary

Planets are subject to the same laws of motion as here on earth. Units are m/s so an example would be 10 m/s. All falling objects accelerate at the same rate (neglecting air resistance) On earth, this is around 10 m/s. This means that on earth, a falling object will increase its speed by 10 m/s every second. Galileo showed that this acceleration is the same for all objects in a vacuum. This was in direct contradiction with the teachings of aristotle who taught that heavier objects must fall faster than light ones. Galileo was proven correct when during the apollo 15 mission, david scott dropped a feather and a hammer at the same time on the moon. They hit the ground at the same time thus proving galileo correct. This worked because the moon has no atmosphere. All objects accelerate at the same rate regardless of whether they are moving horizontally or vertically.