Given,
The force applied by Tory, F=60 N
Mechanical advantage after adding the second pulley, MA=2
As Tory applies 60 N of force when there is only one pulley, the weight of the ball is 60 N.
Thus the output force is 60 N.
The mechanical advantage is given by,
On substituting the known values,
Thus the minimum input force tory need to apply is 30 N