A boy jumping on a trampoline feels three times his normal weight when he lands on the trampoline surface.
Which free body diagram best represents this situation in terms of the forces acting on the boy while he feels this sensation of three times his normal weight?
The upward forces represented are exerted by the trampoline on the boy. The downward forces are the forces exerted by the earth on the boy. $m$ stands for the boy's mass and $g$ for what is usually called the acceleration of gravity. The amounts of force are all expressed in terms of $m$ and $g$.