Question

In the given figure, the block of mass $m$ is dropped from the point $'A'$. The expression for kinetic energy of block when it reaches point ' $B$ ' is :

• A. $\frac{1}{2} mg y _{0}^{2}$
• B. $\frac{1}{2} mgy ^{2}$
• C. $m g\left( y - y _{0}\right)$
• D. $m g y_{0}$

Answer 1

Answer: (D)

Work done by gravity $= K _{ B }- K _{ A }$
$mgy _{0}= K _{ B }-0$
$K _{ B }= mgy _{0}$