Ohm's law - Impossible During a time interval of 15 s, a charge of 50 C flows through a conductor. What is the intensity of the electric current? Determine the resistance of a copper wire whose length is 30 m and a cross section is 6.8 x 10 ^ −6 m2. (rho = 1.72 x 10 ^ -8 m Ω) Determine the intensity of the electric current through a 40 Ω resistor by applying a potential differential of 120 V. Calculate the potential difference applied to a 10 Ω resistor and 2 A flows through it. Determine the power of a refrigerator whose voltage is 120 V and the intensity of the electric current is 3.5 A. With reference to the refrigerator, how much energy does it consume if it runs for 8 hours?

In the sport of parasailing, a person is attached to a rope being pulled by a boat while hanging from a parachute-like sail. a rider is towed at a constant speed by a rope that is at an angle of 15 ∘ from horizontal. the tension in the rope is 1900 n. the force of the sail on the rider is 30∘ from horizontal. what is the weight of the rider? express your answer with the appropriate units.

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

Explain the comparisons between nature and packingtown that appears on pages 81 and 82 answer