1 / 13

Conservation of Momentum

Conservation of Momentum. Conservation of Momentum. For a collision occurring between two objects in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision

ruth-perez
Télécharger la présentation

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. Conservation of Momentum

  2. Conservation of Momentum • For a collision occurring between two objects in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision • The momentum changes are equal in magnitude but opposite in direction (m1·v1) + (m2·v2 ) = -(m1·v1 ) - (m2·v2)

  3. Conservation of Momentum (m1·v1) + (m2·v2 ) = -(m1·v1 ) - (m2·v2) The left side of the equation represents the INITIAL /BEFORE information The right side of the equation represents the FINAL/AFTER information

  4. Example: Conservation of Momentum A 76 kg boater steps off a canoe (which is at rest) to the right onto a dock. If the canoe has a mass of 45 kg and the boater steps out of the canoe with a velocity of 2.5 m/s and then stops, what is the final velocity of the boat? (m1·v1) + (m2·v2 ) = -(m1·v1 ) - (m2·v2) (76·2.5) + (45·0 ) = -(76·0 ) - (45·v2) 190 = -45v2 190 = -45v2 -45 -45 -4.2 m/s = v2

  5. Similar conceptual picture…think about how the idea of Conservation of Momentum relates to Newton’s 3rd Law

  6. Inelastic Collisions • Collisions in which two objects stick together after the collision so that they share the final velocity • Formula: m1v1 + m2v2 = (m1 + m2)vf

  7. Example: Inelastic Collision A 0.500 kg cart moving east with a speed of .928 m/s collides with a 1.50 kg cart moving west with a speed of .216 m/s. If the two carts stick together and move as a single object after the collision then determine the post-collision speed of the two carts.

  8. Answer m1v1 + m2v2 = (m1 + m2)vf (.500 ·.928) + (1.50 · -.216) = (.500 + 1.50)vf (.464) + (-.324) = (2.00)vf .14 = (2.00)vf 2.00 2.00 .07 m/s (to the right) = vf

  9. Elastic Collisions Collision in which the two objects bounce off each other after the collision so that they continue to move separately Formula: (m1·v1) + (m2·v2 ) = (m1·v1 ) + (m2·v2)

  10. Example: Elastic Collision A .015 kg marble moving to the right at .225 m/s collides head-on with a .030 kg marble moving to the left at .180 m/s. After the collision, the smaller marble moves to the left at .315 m/s. What is the velocity of the larger marble after the collision?

  11. Answer (m1·v1) + (m2·v2 ) = (m1·v1 ) + (m2·v2) (.015·.225) + (.030·-.180) = (.015·-.315) + (.030·v2) (.0034) + (-.0054) = (-.0047) + (.030)v2 -.002 = -.0047 + .030v2 .0027 = .030v2 .09 m/s (to the right) = v2

More Related