Answer:
The mechanical advantage of the pulley is 1.
Step-by-step explanation:
The mechanical advantage of the pulley is given as

Here, MA is represent for the mechanical advantage of the pulley, F is load for lift and f applied force.
Given F =21 N and f= 21 N.
Substitute the given values, we get

MA = 1.
Thus, the mechanical advantage of the pulley is 1.