A lift pump itself delivers water only on the upperstroke true or false

Water-lifting devices are used to lift water to a height that allows users easy access to water. ... Other devices, such as the air-lift pump, are not included because they are not applicable to drinking-water supply systems. 4.2 Rope and bucket1. 4.2.1 The technology. This device is mainly used with hand-dug wells.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia

find the sum of the two horizontal vectors and the sum of the two vertical vectors

isoceles right angled triangle