the answer should be "fluids".
Answer: 100lbs
Explanation: The Earth pushes you down at 100lbs, so you push down the earth by 100lbs which is enough to keep you firmly attached to the ground and not allow you to jump more than a couple of feet.
When Emmett is lifting a box
vertically, the forces that must be added to calculate the total force are: the
gravitational force, tension force(the force exerted by Emmett to the box and
the force exerted by the box to Emmett), and air resistance force.