Answer
a) $\sqrt{2gl}$
b) $\sqrt{1.2gl}$
Work Step by Step
a) $E_{Pi}+E_{Ki}=E_{Pf}+E_{Kf}$
$mgl=\frac{mv^2}{2}$
$v=\sqrt{2gl}$
b) $mgl=\frac{mv^2}{2}+mg(0.4l)$
$v=\sqrt{1.2gl}$
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