Question

A man weighing 450 N sits on a platform suspended from a movable pulley and raises himself by a rope passing over a fixed pulley. Assuming the ropes parallel, what force does he exert?

Answer 1

For this arrangement, ignoring friction, stiffness of the rope, etc, upward force on the platform will be twice the force on the man's hand.

$450 - F = 2F$

$3F = 450$

$F = 150N$

F is Force.