A pump is rated at 400 psi. It is working against a 100 ft head of water. What is the available pressure after the loss from the 100 ft of head?

To understand the problem, we need to convert the head of water measured in feet into equivalent pressure in psi. The pressure created by 100 feet of water can be calculated using the formula:

Pressure (psi) = Head (ft) x 0.433

Here, we substitute 100 feet:

Pressure (psi) = 100 ft x 0.433 = 43.3 psi

This value represents the pressure that is lost due to the head of water the pump is working against.

Given that the pump is rated for 400 psi, we need to determine the available pressure after accounting for the loss caused by the 100 ft head. We do this by subtracting the pressure loss from the pump's rated pressure:

Available pressure = Rated pressure - Pressure loss

Available pressure = 400 psi - 43.3 psi = 356.7 psi

When rounding this value, it is reasonable to approximate it to 357 psi.

Therefore, the choice that represents the available pressure after losses from the 100 ft head is 357 psi.