Ch. 3 & 4 Motion & Forces V. Nonlinear Motion  Projectile Motion  Circular Motion  Free-fall

A. Projectile Motion Projectile  any object thrown in the air  acted upon only by gravity  follows a parabolic path called a trajectory  has horizontal and vertical velocities PROJECTILE MINI-LAB

A. Projectile Motion Projectile Velocities Horizontal and vertical velocities are independent of each other!

A. Projectile Motion Horizontal Velocity  depends on inertia  remains constant Vertical Velocity  depends on gravity  accelerates downward at 9.8 m/s 2

ConcepTest A moving truck launches a ball vertically (relative to the truck). If the truck maintains a constant horizontal velocity after the launch, where will the ball land (ignore air resistance)? A) In front of the truck B) Behind the truck C) In the truck C) In the truck. The horizontal velocity of the ball remains constant and is unaffected by its vertical motion. Animation from “Multimedia Physics Studios.”Multimedia Physics Studios

B. Circular Motion Centripetal Acceleration  acceleration toward the center of a circular path  caused by centripetal force B-BALL DEMO PLATE DEMO

B. Circular Motion On the ground...  friction provides centripetal force

B. Circular Motion In orbit...  gravity provides centripetal force ROUND LAB

B. Circular Motion In orbit...  Which satellites travel faster? Near-Earth Satellites Geostationary Satellites

B. Circular Motion Extra Credit  Use the NASA Liftoff web site to find the International Space Station (“STATION”) in the sky this weekend.  liftoff.msfc.nasa.gov/realtime/Jpass/20/ liftoff.msfc.nasa.gov/realtime/Jpass/20/  Write a brief description of your sighting - time, appearance, & other observations.

C. Free-Fall Free-Fall  when an object is influenced only by the force of gravity Weightlessness  sensation produced when an object and its surroundings are in free-fall  object is not weightless! CUP DEMO

C. Free-Fall Weightlessness  surroundings are falling at the same rate so they don’t exert a force on the object

C. Free-Fall NASA’s KC “The Vomit Comet” Go to NASA.NASA Go to CNN.com.CNN.com Go to Space Settlement Video Library.Settlement Video Library Space Shuttle Missions

ConcepTest 1 TRUE or FALSE: An astronaut on the Space Shuttle feels weightless because there is no gravity in space. FALSE! There is gravity which is causing the Shuttle to free-fall towards the Earth. She feels weightless because she’s free-falling at the same rate.

ConcepTest 2 Describe the path of a marble as it leaves the spiral tube shown below. It will travel in a straight line since the tube is no longer exerting a net force on it.