Question

A man has to lift a sack of sugar weighing 240 N. If he uses a single fixed pulley,
how much effort will he need to apply? What will be the mechanical advantage?​

Answer 1

Explanation:

The first difference while lifting a load with a fixed pulley and with a movable pulley is the direction along which the force is applied. In a fixed pulley, the effort will be applied downwards to move the load upwards while in case of movable pulley the direction of effort will be upward for pulling the load up.

 

Also, the mechanical advantage (MA) is the factor by which the input force i.e., the effort is amplified be a mechanical tool. It is the ratio of output force (Load) to the input force (effort).  

MA of a fixed pulley = 1. i.e., the effort required to balance a load of 50kgf = Load / MA = 50 kgf (same as that of the load.

MA of a movable pulley = 2. i.e., the effort required to balance a load of 50kgf = Load / MA = 25 kgf (half as that of the load.