Question

emmett is lifting a box vertically. which forces are necessary for calculating the total force?
○ (f_p), (f_h) and (f_g)
○ (f_p) and (f_n)
○ (f_p), (f_n), and (f_t)
○ (f_p) and (f_g)

Explanation:

When lifting a box vertically, the force applied by the person ($F_p$) and the force of gravity ($F_g$) acting on the box are the main forces to consider. There is no horizontal - related force ($F_h$) here as the motion is vertical. Normal force ($F_N$) acts perpendicular to a surface and is not relevant in pure vertical lifting without contact with a surface in the vertical direction. Frictional force ($F_f$) is also not applicable in this simple vertical - lifting scenario.

Answer:

D. $F_p$ and $F_g$