The actual mechanical advantage (AMA) of a machine is defined as the ratio of the output force (F_out) to the input force (F_in):
\[ AMA = \frac{F_{out}}{F_{in}} \]
Given:
- AMA = 8
- Input force, \( F_{in} = 400 \) N
We can rearrange the formula to solve for the output force:
\[ F_{out} = AMA \times F_{in} \]
Substituting the values:
\[ F_{out} = 8 \times 400 , \text{N} = 3200 , \text{N} \]
Thus, the output force on the short end of the crowbar is:
\[ \boxed{3200 , \text{N}} \]