To calculate the coefficient of static friction ($\mu_s$), we use the following formula:

$F_{\text{friction}} = \mu_s \cdot F_{\text{normal}}$

Where:

• $F_{\text{friction}}$ is the maximum static friction force (28.9 N),
• $F_{\text{normal}}$ is the normal force, which is equal to the weight of the box (mass $m = 34.5 \, \text{kg}$) times the acceleration due to gravity ($g = 9.81 \, \text{m/s}^2$).

First, we calculate the normal force:

$F_{\text{normal}} = m \cdot g = 34.5 \, \text{kg} \times 9.81 \, \text{m/s}^2$

Now let's solve for ( F_{\text{normal