1 / 16

Lecture no 17&18 Conservation of Momentum

Lecture no 17&18 Conservation of Momentum. Prepared by Engr.Sarfaraz Khan Turk Lecturer at IBT LUMHS Jamshoro. Momentum.

jdurham
Download Presentation

Lecture no 17&18 Conservation of Momentum

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Lecture no 17&18Conservation of Momentum Prepared by Engr.Sarfaraz Khan Turk Lecturer at IBT LUMHS Jamshoro

  2. Momentum • In classical mechanics, linear momentum or translational momentum (pl. momenta; SI unit kgm/s, or equivalently, Ns) is the product of the mass and velocity of an object. For example, a heavy truck moving fast has a large momentum—it takes a large and prolonged force to get the truck up to this speed, and it takes a large and prolonged force to bring it to a stop afterwards. If the truck were lighter, or moving more slowly, then it would have less momentum. • Like velocity, linear momentum is a vector quantity, possessing a direction as well as a magnitude:p=mv

  3. Momentum • Linear momentum is also a conserved quantity, meaning that if a closed system is not affected by external forces, its total linear momentum cannot change. In classical mechanics, conservation of linear momentum is implied by Newton's laws; but it also holds in special relativity (with a modified formula) and, with appropriate definitions, a (generalized) linear momentum conservation law holds in electrodynamics, quantum mechanics, quantum field theory, and general relativity.

  4. Conservation of Momentum

  5. Conservation on Momentum • In the absence of an external force the momentum of a closed system is conserved.

  6. Law of Conservation of Momentum In a closed system,the vector sum ofthe momenta before and after an impact must be equal. Before After m1v1 +m2v2 = m1v1’ + m2v2’

  7. Closed System: • A system that has no gain nor loss of mass.

  8. Isolated System: • A closed system with no net external force acting on it.

  9. Internal and External Forces • Internal Forces: act between objects within a system. • External Forces: are exerted by objects outside the system.

  10. Question • A stationary firecracker explodes. What is the total momentum of the pieces that it breaks into? Coyle ,4th of July 2009, Hudson River

  11. Example: Recoiling Cannon

  12. Example 1: Recoiling Cannon A cannon of mass 750kg shoots a cannon ball of mass 30kg with a velocity of 20m/s. Find the recoil velocity of the cannon. m1v1 +m2v2 = m1v1’ + m2v2’ Answer: -0.8m/s

  13. Collisions • Elastic (Kinetic Energy is conserved) • Inelastic (Kinetic Energy is not conserved) • Deformed objects • Objects stick together • Note: Momentum is conserved in both types of collisions.

  14. Example 2: Inelastic Collision • A bullet of mass 0.010kg is shot at a speed of 30m/s towards a 5kg stationary block. The bullet becomes embedded in the block an the two fly off together. • Find the speed with which they fly off. Answer: 0.06m/s

  15. Problem 3 • A 45 kg student is riding on a 7kg scateboard with a velocity of +4m/s. The student jumps of the cart with a velocity of -1m/s. Find the velocity of the scateboard after the student jumped off. • Answer: +36m/s

More Related