p111_lecture15

p111_lecture15 - 7.5 Center of Mass The center of mass is a...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
7.5 Center of Mass The center of mass is a point that represents the average location for the total mass of a system. 2 1 2 2 1 1 m m x m x m x cm + + =
Background image of page 1

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

View Full DocumentRight Arrow Icon
7.5 Center of Mass 2 1 2 2 1 1 m m x m x m x cm + ! + ! = ! 2 1 2 2 1 1 m m v m v m v cm + + = The motion of the center-of-mass is related to conservation of momentum. Consider the change in the positions of the masses in some short time Δ t : Divide by Δ t
Background image of page 2
7.5 Center of Mass 2 1 2 2 1 1 m m v m v m v cm + + = In an isolated system, the total linear momentum does not change, therefore the velocity of the center of mass does not change. } P 2 1 m m + = P
Background image of page 3

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

View Full DocumentRight Arrow Icon
7.2 The Principle of Conservation of Linear Momentum Example: Ice Skaters Starting from rest, two skaters push off against each other on ice where friction is negligible. One is a 54-kg woman and one is a 88-kg man. The woman moves away with a speed of +2.5 m/s. Find the recoil velocity of the man.
Background image of page 4
7.2 The Principle of Conservation of Linear Momentum o f P P r r = 0 2 2 1 1 = + f f v m v m 2 1 1 2 m v m v f f ! = ( ) ( ) s m 5 . 1 kg 88 s m 5 . 2 kg 54 2 ! = + ! = f v
Background image of page 5

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

View Full DocumentRight Arrow Icon
7.5 Center of Mass 0 2 1 2 2 1 1 = + + = m m v m v m v cm BEFORE AFTER 0 ! = = cm v (54 kg)(+2.5 m/s) + (88 kg)(-1.5 m/s) 54 kg + 88 kg 0.02 Consider the “Ice Skater” example which was an isolated system:
Background image of page 6
Chapter 8 Rotational Kinematics
Background image of page 7

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

View Full DocumentRight Arrow Icon
8.1 Rotational Motion and Angular Displacement In the simplest kind of rotation, points on a rigid object move on circular paths around an axis of rotation.
Background image of page 8
8.1 Rotational Motion and Angular Displacement The angle through which the object rotates is called the angular displacement. o ! " = #
Background image of page 9

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

View Full DocumentRight Arrow Icon
8.1 Rotational Motion and Angular Displacement DEFINITION OF ANGULAR DISPLACEMENT When a rigid body rotates about a fixed axis, the angular displacement is the angle swept out by a line passing through any point on the body and intersecting the axis of rotation perpendicularly. By convention, the angular displacement is positive if it is counterclockwise and negative if it is clockwise.
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/03/2011 for the course PHY 111 taught by Professor Bolland during the Fall '10 term at Ohio State.

Page1 / 38

p111_lecture15 - 7.5 Center of Mass The center of mass is a...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online