Manuel is holding a 5kg box how much force is he exerting on it

Mass = 5kg

acceleration due to gravity = 9.8 m/s²

Notice that we only have to work with vertical components,

__Fn = ma (normal force Manuel exerts on box) (upward direction)

__Fw = mg (weight of box) (downward direction)

Because there is no change in motion, the sum of the vertical components should be equal to 0 or balance each other out. Therefore,

ΣFy = Fn + (-Fw)

0 = Fn + (-mg) [solve for Fn]

mg = Fn

(5kg) (9.8m/s²) =

49 N = Fn = Force that Manuel is exerting on box (upward direction)