Average velocity, \(v_{\text {avg }}=\frac{\text { displacement }}{\text { total time }}\)
Given, \(y=7 \sin (\pi t) m , t=0\) to \(0.5\)
\(y\) at \(t=0, x_1=7 \sin \left(0^{\circ}\right)=0\)
\(y\) at \(t=0.5\),
\(x_2=7 \sin (\pi / 2)=7\)
\(\therefore V_{\text {avg }}=\frac{7-0}{0.5-0}=14\)
\(v_{\text {avg }}=14 m / s\)
$\left(g=10 \,{m} / {s}^{2}\right)$