(19) Elastic and Inelastic Collisions

# (19) Elastic and Inelastic Collisions - Lecture 19 Elastic...

This preview shows pages 1–8. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Lecture 19 Elastic and Inelastic Collisions Energy versus Momentum Energy versus Momentum • Energy is a scalar • Momentum is a vector • Transfer of energy by a force=work • Transfer of momentum by a force=impulse • Energy comes in a multitude of forms • There is just one kind of momentum ACT: Bowling pin You want to knock down a large bowling pin by throwing a ball at it. You can choose between two balls of equal mass and size. One is made of rubber and bounces back when it hits the pin. The other is made of putty and sticks to the pin. Which ball do you choose? v A. The rubber ball. B. The putty ball. C. It makes no difference. p p’ p+p’ rubber p putty Collisions, explosions These are situations where int er nal ext er nal F F Total linear momentum is conserved. ext er nal ~ 0 F Or: The momentum transfer due to the internal forces is much larger than that due to external forces. What happens to the total kinetic energy? Special case: Perfectly inelastic collisions , when the objects stick together. Example: Pin and putty 1. Constant K 2. K decreases 3. K increases One body breaks into a number of parts. The explosion mechanism provides the extra energy. Explosions Superelastic collisions Some internal energy is transformed into KE because of a collision. Example: An excited atom hits another atom and drops to a lower state without radiation. Whenever a deformation is involved. Example: Most macroscopic collisions Inelastic collisions When internal forces are conservative or objects are “hard”. Examples: Elementary particles, billiard balls Elastic collisions 1D Inelastic: Shooting at a block A block of mass M is initially at rest on a frictionless horizontal surface. A bullet of mass m is fired at the block with speed v. The bullet lodges in the block. Determine the final speed of the block (with the bullet)....
View Full Document

## This note was uploaded on 03/27/2008 for the course PHYS 221 taught by Professor Herrera-siklody during the Fall '08 term at Iowa State.

### Page1 / 24

(19) Elastic and Inelastic Collisions - Lecture 19 Elastic...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online