Jan 30 8:48 PM Momentum the momentum of an object is the product of its mass and velocity i.e. how hard it is to stop something vs. inertia: momentum is a vector quantity the main equation used to find the momentum of an object: Jan 30 8:44 PM Train hits car video Spiderman train video Train hits cow video Jan 30 8:51 PM 1
p.451 Jan 27 7:00 PM p.451 Jan 27 7:02 PM The Example That's Not in Your Book: A 1.50 kg object falls from a height of 14.0 m. What is the momentum of the object as it hits the ground? Jan 28 1:45 PM 2
Sep 5 11:55 AM Jan 29 9:57 PM p.452 Jan 27 7:03 PM 3
p.452 Jan 27 7:03 PM p.453 #1 2, 5 9, 11, 13 16 Jan 27 8:08 PM Jan 29 10:00 PM 4
Impulse Impulse is the change in momentum experienced by an object impulse is a vector quantity the main equation used to find impulse (from Newton's Second Law) think "impulse" when you see this: Jan 30 9:12 PM p.458 Feb 1 9:19 AM p.458 Feb 1 11:48 AM 5
Sep 5 11:56 AM Sep 5 11:56 AM Jan 29 10:04 PM 6
Impulse (Qualitative) the impulse equation explains 2 scenarios: 1. (ledge jumper video) 2. (hockey shot video) Feb 1 9:32 AM Impulse (Graphs) the area between the x axis and the line on an F vs. t graph represents impulse any area above the x axis is positive, while below the x axis is negative change in velocity of the object can be found by using an F vs. t graph and the equation Feb 1 9:26 AM p.462 Feb 1 9:26 AM 7
p.462 Feb 1 9:30 AM p.453 Jan 29 10:08 PM p.467 #1 13 Jan 29 4:27 PM 8
Jan 29 10:09 PM Jan 29 10:10 PM Jan 29 10:02 PM 9
Jan 29 10:02 PM Conservation of Momentum (Lethal Weapon buckshot video) In an isolated system, momentum will always remain constant (i.e. it is conserved) This is useful in the analysis of collisions and explosions. If we examine the momenta immediately before and immediately after the collision or explosion, they will be the same. Note that while the total momentum in an isolated system will stay the same, the momentum of individual objects within the system can change (i.e. impulse). Equation: Feb 9 9:11 AM p.477 Sep 6 7:54 AM 10
p.477 Sep 6 7:54 AM p.478 Sep 6 7:55 AM p.478 Sep 6 7:55 AM 11
p.479 Sep 6 7:55 AM p.479 Sep 6 7:56 AM Jan 31 9:35 AM 12
Jan 31 9:43 AM Jan 31 9:52 AM Jan 31 9:53 AM 13
Jan 31 9:53 AM p.475 Sep 6 7:56 AM p.475 Sep 6 7:57 AM 14
Jan 31 9:43 AM Types of Collisions Elastic collision: momentum and kinetic energy are conserved Inelastic collision: only momentum is conserved; KE is not conserved Elastic Inelastic Momentum Conserved? Kinetic Energy Conserved? Objects Bounce Apart? Feb 8 3:51 PM p.482 Feb 11 9:06 AM 15
p.482 Feb 11 9:07 AM p.486 Sep 11 7:43 AM 2D Conservation of Momentum When analyzing a collision of explosion in 2 dimensions, break the problem into 2 separate problems (the x component and the y component) then recombine them. When analyzing the x component, ignore any y components. When analyzing the y component, ignote any x components. Recombine x and y components by drawing a right angled vector diagram, and using the pythagorean theorem and trig. Feb 1 9:41 AM 16
Jan 31 9:58 AM p.492 Feb 8 3:42 PM p.492 Feb 8 3:42 PM 17
p.495 Feb 8 3:46 PM p.495 Feb 8 3:48 PM Jan 31 9:46 AM 18
Jan 31 9:47 AM Jan 31 9:54 AM Jan 31 9:56 AM 19
Jan 31 9:56 AM p.490 Feb 8 3:48 PM p.491 Feb 8 3:48 PM 20
Jan 31 9:47 AM Jan 31 9:55 AM p.499 (#1 3, 5 11) Feb 8 3:50 PM 21
p.499 #6 (This is from Check and Reflect...we are using it as an example) Feb 11 9:09 AM p.496 Feb 11 9:09 AM p.486 (#1 11) Feb 11 9:14 AM 22
Jan 31 9:49 AM Jan 31 9:57 AM 23