Monday 23 Nov:

 

Journal Review: Find the center of mass (COM)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Torque Problem (from lower left corner):

(x axis: Center of Gravity is CCWt)

 

CCWt = CWt + CWt

   Fd  =  Fd  + Fd

132x = (100)(5) + (32)(14)

 

132x = (500) + (448)

x = 948/132 = 7.18

 

 

 

(y axis: Center of Gravity is CWt)

 

CWt = CCWt + CCWt

   Fd  =  Fd  + Fd

132y = (100)(5) + (32)(8)

 

132y = (500) + (256)

y = 756/132 = 5.73

 

 

 

 

 

 

 

Target: Understanding Waves

Ch #11:

 

 V = (f)(l)

 

 

 

Wavelength (l) = 2 wave segments

 

 

 

 

 

The next longest standing wave in a tube of length in a tube of length L with one open end and one closed end is the third harmonic.  It also has a displacement antinode at one end and a node at the other.

 

Transverse Waves:

 

  1. In general, sound is conducted from slowest through fastest through (which medians)?

 

 

 

 

 

 

 

 

 

 

 

    1. vacuum,  then cold air, warm air, liquids, solids

 

  1. Compared to the velocity of a 400 Hz sound, the velocity of 100 Hz sound through air is:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                        Same Velocity! Velocity of sound does not depend on frequency, but on temperature, pressure and density (in a confined space, the speed of sound increases with temperature)

 

  1. On a day when the speed of sound in air is 340 m/s, a bat hitting a ball emits a crack whose reaches it 0.50 s later.  How far way was the object that reflected back the sound?

                  

 

 

 

 

 

 

 

 

 

 

 

 

     

            Dist = (V) (t) with no acceleration

             x =  (340)(0.5) = 170m/s

 

 

 

 

 

Work on Free Response

Quiz Wed