Question

Using a simple machine, a student is able to lift a 500N weight by applying only 100N.

Answer 1

The mechanical advantage of a machine is the ratio between the output force and the input force:
$MA= \frac{F_O}{F_I}$
In our problem, the input force is 100 N, while the output force is the weight of the object the student lifts, 500 N. So, the mechanical advantage is
$MA= \frac{500 N}{100 N}=5$