To find the missing acceleration when the net force is 20.0 N and the mass is 5.0 kg, we can use Newton's second law of motion, which states that \( F = m \times a \), where \( F \) is the net force, \( m \) is the mass, and \( a \) is the acceleration.
Using the given values for the third row:
- Net force (F) = 20.0 N
- Mass (m) = 5.0 kg
Rearranging the equation to solve for acceleration (a) gives us:
\[ a = \frac{F}{m} \]
Substituting the given values:
\[ a = \frac{20.0 , \text{N}}{5.0 , \text{kg}} = 4.0 , \text{m/s}^2 \]
Therefore, the value that would complete the last cell is 4.0.