Question

A tidal wave can be described as a simple harmonic wave. If the tidal wave's amplitude is 0.30 m, what is it's max velocity and acceleration.

Im using the wave equation and i end up with a negative acceleration and velocity, which for me doesn't make sense. this is what i've made so far: http://prntscr.com/2cevl8

Answer 1

Maximal valeues, or amplitudes, are alays positive.

If it appears negative from your calculation, simply change phases such as :

u = A cos (wt)
v = -wA sin (wt) = wA cos (wt + pi/2)
a = -w²A cos wt = w²A coq (wt + pi)

Answer 2

Oh yea, of course, thank you very much :)