Final answer:
The greatest pressure exerted by the block is 125N/m², while the least pressure exerted is 187.5N/m².
Step-by-step explanation:
The pressure exerted by an object is the force applied per unit area. To calculate the pressure exerted by the rectangular block on the table, we need to find its surface area. The greatest pressure is exerted when the block is standing on its end, and the least pressure is exerted when the block is lying flat.
To calculate the greatest pressure, we use the formula:
Pressure (P) = Force (F) / Area (A)
Given that the weight of the block is 15N, the force is 15N. The area is equal to the base of the block, which is 40cm x 30cm = 1200cm² = 0.12m². Therefore, the greatest pressure is:
Pressure = 15N / 0.12m² = 125N/m²
To calculate the least pressure, we use the same formula but with a different area. The area is equal to the area of the block's base, which is 40cm x 20cm = 800cm² = 0.08m². Therefore, the least pressure is:
Pressure = 15N / 0.08m² = 187.5N/m²