The forces the people exert on the plank is 100.45N
Explanation:
Force of man 1 on plank = [tex]F_1[/tex]
Force of man 2 on plank = [tex]F_2[/tex]
[tex]\bold{\text{ \bold{ Acceleration due to gravity}} = 9.8 m/s^2}[/tex]
Gravitational force on plank = [tex]\bold{m\times a = 4.25\times 9.8 = 41.65N}[/tex]
Gravitational force on box = [tex]\bold{m\times a= 6\times 9.8 = 58.8N}[/tex]
Given hint is forces of people is equal to forces on plank and box
[tex]\bold{\Rightarrow F-1 + F_2 = 41.65 + 58.8 = 100.45N}[/tex]
in the state of equilibrium normal force is equal and opposite to gravitational force.
