Question

How much work (in J) must the man do to pull in the blocks. Round off to closest integer.

Answer 1

$K_i=\frac{1}{2}{I}_1{\omega }_1^2$
$=\frac{1}{2}[1.6+(2\left)\right(4\left)\right(0.9{)}^2\left]\right(0.5\times 2\pi {)}^2$
$=39.9J$
$K_f=\frac{1}{2}[1.6+(2\left)\right(4\left)\right(0.15{)}^2\left]\right(14.3{)}^2$
$=181J$
$W=K_f-K_i=141.1J$