To estimate the minimum and maximum coefficient of friction between the wooden skids and the concrete surface, you can consider the following approach:
Determine the weight of the building: The weight of the building is given as 15,000 kg.
Calculate the normal force: The normal force acting on the skids is equal to the weight of the building, which is 15,000 kg multiplied by the acceleration due to gravity (9.8 m/s²). So, the normal force is: Normal force = (15,000 kg) × (9.8 m/s²) = 147,000 N
Estimate the maximum frictional force: The maximum frictional force can be estimated by multiplying the normal force by the maximum coefficient of friction. Let's assume the maximum coefficient of friction between wood and concrete is 0.6 (a common value for dry wood on concrete). Therefore, the maximum frictional force is: Maximum frictional force = (0.6) × (147,000 N)
Estimate the minimum frictional force: To estimate the minimum frictional force, you can assume the minimum coefficient of friction. This value will depend on the condition of the skids and the surface of the concrete. If the concrete is smooth and the skids are in good condition, a conservative estimate for the minimum coefficient of friction could be around 0.3. Therefore, the minimum frictional force is: Minimum frictional force = (0.3) × (147,000 N)
With these estimates of the minimum and maximum frictional forces, you can determine the range of winching forces required to move the building. It is important to consider safety factors and account for any additional factors that may affect the friction, such as moisture, surface irregularities, or contaminants on the skids or concrete.