$y = a\sin 2\pi \,\left( {\frac{t}{T} - \frac{x}{\lambda }} \right)$==> $T = 0.04 sec$
==> $v = \frac{1}{T} = 25Hz$
Also ${(A)_{\max }} = {\omega ^2}a = {\left( {\frac{{2\pi }}{T}} \right)^2} \times a = {\left( {\frac{{2\pi }}{{0.04}}} \right)^2} \times 3$
$=7.4 \times 10^4 cm/sec^2.$

