What is the magnitude of the average force exerted on the leg, in newtons, taking the effective mass of the hand and forearm to be 1.6 kg

15.696N

Explanation:

According to Newton's second law of motion,

Force = mass × acceleration due to gravity

Given

Mass = 1.6kg

Acceleration due to gravity = 9.81m/s²

Substitute to get the force

Force = 1.6×9.81

Force = 15.696N

Magnitude of the average force is 15.696N

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.