for all parts of this problem, assume the effects of viscosity are negligible (a) the water cannon in the seattle center international fountain launch bursts of water 35 meters vertically into the air. before the cannon nozzle opens, the water inside is stationary. what pressure is the water under at the instant the launch begins? (b) from the mid- f= ? n term of winter 2012: a container with two moveable pistons is filled with incompressible oil with a specific gravity of 0.8. the larger piston has an area of 10,000 mm2 and on it is a car with a weight of 10,000 n and a specific gravity of 2.0. how much force must be applied to the smaller piston (which has an area of 10 mm") to keep the car at a constant height? 10,000 n a = 10 mm2 a = 10,000 mm2

i believe the answer is b.

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

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