Class 39: Center of mass Course Evaluation: 1. Started yesterday Apr - PowerPoint PPT Presentation

Class 39: Center of mass

Course Evaluation: 1. Started yesterday Apr 13 th , ends Dec 29 th (Wednesday). 2. Go to http://pa.as.uky.edu/ 3. Click at “UNDERGRADUATES” in the top menu and then choose the first item: Physics & Astronomy Course Evaluations 4. Follow instructions from there. 5. Make sure remember or write down any given key or password. You need this to re-enter the system if you cannot finish the evaluation in one time.

Example F= -kx x x=0 A 0.1kg mass is attached to a spring of spring constant 160N/m and set to oscillate. At t=0 the position of the mass is +2cm and moving with a velocity of +0.6m/s. Calculate  . A, and  and then predict its position, veolicty, and acceleration at t=0.02s.

Six degrees of freedom (x,y,z) (x,y,z) Translational motion You need: (i) Three parameters (coordinates) to fix the position of a point in the rigid body. (ii) Three angles to fix the orientation of the object. Rotational motion

Center of mass z m 2 m 1 m 3 y m 5   m x m x   m 4 i i i i  m x m x m x    1 1 2 2 N N i i x  x   CM  m m m m M 1 2 N i total i   m y m y    i i i i m y m y m y    1 1 2 2 N N i i y    CM  m m m m M 1 2 N i total i   m z m z   i i i i  m z m z m z    1 1 2 2 N N i i z    CM  m m m m M 1 2 N i total i

Example 1m 1m 1m 1m 1m 1m Calculate the position of the CM of the uniform sheet of metal shown in the figure.