a man of mass 60kg carries a bag of weight 60N on his sholder. what will be the force with the floor pushes up his feet?
Weight of the man, W = mg = (60 x 10) N = 600 N ( g= 10 m/s2)
Weight of the bag, W' = 60 N
Total force exerted on the ground, F = W + W' = 660 N
The force exerted by the ground on the man is 660 N.
This is due to the third law of motion which stated that every action, there is always an equal and opposite reaction that acts on different bodies.
Here the man and the bag form one system acting on the ground with force F and the ground exerts an equal but opposite force F on the system.