## Waves and Oscillatiions

A forum set up for physics questions from students in the courses PHYS1121, 1131, 1221 and 1331 at the University of New South Wales. It is intended for questions that cannot readily be answered in class,
either because they fall outside the main syllabus and therefore would be distraction (however interesting) or for other reasons.

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Suvekchhya
Posts: 10
Joined: Sat Jun 07, 2014 7:13 pm

### Waves and Oscillatiions

In the equation
v = -A*w*sin(wt + phi )

why must sin(wt+ phi) be = -1 to obtain maximum value of v ?

is there other ways of finding max of v if k = 8n/m, amplitude = 0.1m, and m = 0.5kg?
thankyou
a.s.h.
Posts: 110
Joined: Tue Jan 28, 2014 3:50 pm

### Re: Waves and Oscillatiions

If you consider a graph of v versus t, it varies between +Aω and -Aω, since the coefficient of that sine is -Aω. So v's greatest value is +Aω, which occurs when that sine is equal to -1.

And to find max. v, one can set x = 0 in the equation v² = (k/m).(a² - x²), k is the spring constant, m is the mass and a is the amplitude, and take the positive square root for v.