ASTR 114 Lecture Notes - Lecture 5: Net Force, The Moons, Escape Velocity

• School: Binghamton University
• Department: Astronomy
• Course: ASTR 114
• Professor: Christopher A.Taylor

Document Summary

Speed: rate at which an object moves: speed = distance/time (m/s) In the absence of friction and air resistance, all falling objects accelerate at the same rate. On earth, that rate is 9. 8 m/s2, also known as gravity (g). Galileo showed that g is the same for all falling objects, regardless of their mass. Mass: the amount of matter in an object. Weight: the force that acts upon an object. The weight of an object depends on the force of gravity on the object. People would weigh less on the moon, because gravity is weaker there. Astronauts are weightless in space because they are in a constant state of free-fall. An object moves at constant velocity unless a net force acts to change its speed or direction (an object in motion will stay in motion). For every action, there is always an equal and opposite reaction. Objects continue at constant velocity because of conservation of momentum.