Waves
posted by Sivashen .
a long fishing rod is kept upright .A boat engine causes the rod to vibrate.Mary speculates that the end of the rod moves to and fro 20 times in 1 minute.The amplitude of the vibrtion is 0.15m.Calculate the speed of the vibration at the end of the fishing rod

See if some of the following links will help:
http://search.yahoo.com/search?fr=mcafee&p=how+to+calculate+the+speed+of+the+vibration+of+a+fishing+rod
Sra 
frequency f = 20 /60 = 1/3 Hz
x = .15 sin (2 pi (1/3) t)
v = .15(2 pi/3) cos (2 pi t/3)
= .1 pi cos (2 pi t/3)
or .1 pi maximum