some questions in BR physics

[batista_123]

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Volume I of BR physics
page 216, #53.
in experiment 1, with his arms outstretched, the student drops the weights. this will cause the angular velocity of the student to:
increase
decrease
remain the same

i think increase, the answer says remain the same because the inertia of the system doesnt change. are you kidding me? if he dropped the weights, doesnt that means the system weighs less and therefore has less inertia?



page 265, #61. a mass collides with another mass which is connected to a spring. there is no friction. now assume there is friction. the friction decreases the subsequent speed of oscillation.
what is speed of oscillation? isn't that frequency? if it is, in the equation for frequency, which is something like 1/2pi m/k or whatever, it seems like the speed should depend on m and k only. no?

longitudinal and transverse waves. I cannot understand whats the difference, no matter how many websites i go to, no matter how many physics books i look up. It seems like the difference is that something is parallel to something else in long and something is perpendicular to something else in transverse???

 

[loveoforganic]

Transverse wave

http://www.youtube.com/watch?v=g49mahYeNgc

Longitudinal wave

http://www.youtube.com/watch?v=m7RYOBj4UGc

 

[phEight]

longitudinal and transverse waves. I cannot understand whats the difference, no matter how many websites i go to, no matter how many physics books i look up. It seems like the difference is that something is parallel to something else in long and something is perpendicular to something else in transverse???

For the waves question, let's imagine a sound wave propagating from your mouth. If you were able to see the effect this wave had on the surrounding air molecules, you would see that the air molecules are being pushed in the same direction as the wave is traveling. Now for a transverse wave, imagine a guitar string (notice now the string is the medium of which the wave travels, not air molecules), so when you pluck the string, the medium moves up and down while the wave is actually propagating down the string, meaning this is a transverse wave, where the vibrations are perpendicular to the direction of propagation. Remember these definitions are the effect the wave has on the medium which it is traveling through. Hope this helps

Those links loveoforganic posted illustrate it nicely