Multiple Cholce Questlon The figure shows a \( 60-\mathrm{lb} \) uniform thin panel placed in a truck with end \( A \) resting on a rough horizontal surface and end \( B \) supported by a smooth vertical surface. Determine the minimum required coefficient of static friction at end \( A \) if the frictional force \( F=6 \mathrm{lb} \). O 1.863 0.1 O 28.5

To solve this problem, we need to analyze the forces acting on the panel and apply the conditions for static equilibrium. ### Known Conditions: 1. Weight of the panel, \( W = 60 \, \text{lb} \) 2. Frictional force at end \( A \), \( F = 6 \, \text{lb} \) 3. The panel is uniform and thin, which means its weight acts at its center of gravity (midpoint). ### Steps to Solve: 1. **Identify Forces**: - The weight \( W \) acts downward at the center of the panel. - The normal force \( N_A \) acts upward at end \( A \). - The frictional force \( F \) acts horizontally at end \( A \). - The normal force \( N_B \) acts horizontally at end \( B \) (since it is a smooth surface, there is no friction). 2. **Static Equilibrium Conditions**: - The sum of vertical forces must equal zero: \[ N_A - W = 0 \quad \Rightarrow \quad N_A = W = 60 \, \text{lb} \] - The sum of horizontal forces must equal zero: \[ F - N_B = 0 \quad \Rightarrow \quad N_B = F = 6 \, \text{lb} \] 3. **Frictional Force**: - The frictional force \( F \) at end \( A \) is related to the normal force \( N_A \) and the coefficient of static friction \( \mu_s \): \[ F = \mu_s N_A \] - Substituting the known values: \[ 6 = \mu_s \cdot 60 \] 4. **Solve for \( \mu_s \)**: \[ \mu_s = \frac{6}{60} = 0.1 \] ### Conclusion: The minimum required coefficient of static friction at end \( A \) is \( 0.1 \). Thus, the correct answer is \( 0.1 \).