Answer
(a) $A = 6.50~mm$
(b) $\lambda = 28.0~cm$
(c) $f = 27.8~Hz$
(d) $v = 7.78~m/s$
(e) The wave is moving in the positive x-direction.
Work Step by Step
We can write the general equation for a wave equation when the wave is moving in the positive x-direction.
$y(x,t) = A~cos[(2\pi)(\frac{x}{\lambda}-\frac{t}{T})]$
(a) $A = 6.50~mm$
(b) $\lambda = 28.0~cm$
(c) $T = 0.0360~s$
We can find the frequency.
$f = \frac{1}{T}$
$f = \frac{1}{0.0360~s}$
$f = 27.8~Hz$
(d) We can find the speed.
$v = \lambda~f$
$v = (0.280~m)(27.8~Hz)$
$v = 7.78~m/s$
(e) The negative sign in $(\frac{x}{\lambda}-\frac{t}{T})$ shows that the wave is moving in the positive x-direction.
