Lesson 13 (Collisions) of Dianna's Intro Physics Class on Physics Girl. Never taken physics before? Want to learn the basics of physics? Need an AP Physics 1 review before the exam? This course is for you! Exercises in this video: 1. Are the following collisions elastic or inelastic? - Asteroid hitting Earth? - Spitball smacking into your friend? - Pool balls hitting each other? - Water balloon hitting your face? - Newton’s cradle? - Bumper cars colliding? - A car crash? - Subatomic particles colliding? - Black holes colliding? 2. A toy train of mass 2kg, traveling at a speed of 12m/s, collides with an identical train at rest. They stick together. What is the new speed of the trains? How much energy was lost to heat in that inelastic collision? 3. A pool ball traveling at 2m/s directly hits an identical, but stationary, pool ball. What are the velocities of each ball after the collision? Special thanks to cosmologist Dr. Katie Mack for her awesome shoutout at the end of the video! You can follow her on Twitter @AstroKatie Credits: Dianna Cowern - Executive Producer/Host/Writer Jeff Brock - Lead Writer/Course Designer Laura Chernikoff - Producer Rachel Watson - Video Editor Sophia Chen - Researcher/Writer Erika K. Carlson - Researcher/Writer Hope Butner - Production Assistant Levi Butner - Videographer Lauren Ivy - Set Design Vanessa Hill - Consulting Producer Aleeza McCant - Illustrator Rachel Allen - Illustrator Consultant - Kyle Kitzmiller Lucy Brock, Samantha Ward - Curriculum Consultants Cathy Cowern - Transcription