Question

A metre stick is held vertically with one end on the floor and is then allowed to fall. The speed of the other end when it hits the floor assuming that the end at floor does not slip, is (g = 9.8 $m/se{c}^2$)

• A. 3.2 m/sec
• B. 5.4 m/sec
• C. 7.6 m/sec
• D. 9.2 m/sec

Answer 1

The correct option is B 5.4 m/sec

$\begin{array}{c}L=1m,H=\frac{L}{2}=0.5m\\ I=\frac{M{L}^2}{3}\end{array}$

using conservation of energy

$\begin{array}{c}mgH=0.5I{w}^2\\ mg\frac{L}{2}=0.5\frac{M{L}^2}{3}{\left(\frac{V}{L}\right)}^2\\ V=\sqrt{3gL}\\ V=5.4m/s\end{array}$