The forces the people exert on the plank is 100.45N
<u>Explanation:</u>
Force of man 1 on plank =
Force of man 2 on plank =
Gravitational force on plank =
Gravitational force on box =
Given hint is forces of people is equal to forces on plank and box
in the state of equilibrium normal force is equal and opposite to gravitational force.
Answer
a) For the rock
b) for maximum range
c) The value of θ is the same on every planet as g divides out.