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Raising a yacht from the seabed by attaching filled air bags to it

A large yacht has a mass of 305 tonnes. The yacht sinks and is lying on the sea bed at a depth of 40m. It is estimated that the volume of teh yacht is such that it displaces 0.8m3 of water when it is totally submerged under water. A salvage team decides to raise the yacht to the surface by fixing large bags to the yacht and

Calculating radiated power of a firecracker

The explosion of the firecracker in the air at a height of 40m produces a 100 db sound level at the ground below. If the threshold of hearing is 10-12Wm-2, what is the instantaneous total radiated power, assuming that it radiates as a point source?

Find the minimum power required in an electricity generating station.

An electricity generating station has a rated output of 300 megawatts. Given that the station heat rate is 12 000kJ/kW-h, and the coal used has a heat value of 23 000kJ/kg, find the minimum possible belt-drive power required for the bunker coal conveyor in order to keep the boiler supplied when the station is on full load. The

Force between charges that are apart in air

Factor of k for air is 8.93x10(power)9 Nm(power)2/C(power)2 Calculate force between charges of +150.0(micro)C and -75.0(micro)C that are 0.600 m apart in air. * I am not able to use the proper symbols for (power), or (micro)

Electromagnetic Induction

Imagine in a remote area of the countryside a 70-kV, 60-Hz power line. A shifty local resident has erected a large open loop just below the line with the intention of drawing power. Is this possible and, if so, how would it be transferred? Where would the energy stolen come from? Would anyone be able to detect the loss? Might it


Multiple choice: 1. An ideal source of emf is connected in seriew with a resistor in closed loop, and a current or 0.e50 A circulates. An additional 6.0-Ohm resistor is added in series, and the current drops to 0.30 A. The original resistance was: (a) 9.0 Ohm (b) 6.0 Ohm (c) 15 Ohm (d) 3.0 Ohm (e) none of these. Explain your ch

Magnetic flux...induced emf...etc...

Consider a rectangular loop of length l (parallel to x) width w (parallel to y) total resistance R, is being pulled at constant force F=fx. If at tiem t=0 it is aligned with the front edge at x=0, has velocity vx, and the magnetic field everywhere is B= 0 x<0 B= BoZ x>0 solve and draw plots for the time dependence of: