Answer:
Effort = 120 Newton
Step-by-step explanation:
Given the following data;
Mechanical advantage = 6
Load = 780 N
To find the effort required to lift the weight;
Mechanical advantage can be defined as the ratio of the load (weight) lifted by a simple machine to the effort (force) applied.
Mathematically, the mechanical advantage is given by the formula;

Making effort the subject of formula;

Substituting into the formula, we have;

Effort = 120 Newton.