The half-life of Cs-137 is 30.2 years. If the initial mass of the sample is 1.00 kg, how much will remain after 151 years? A. There will be 2.000 kg left after 151 years,
B. There will be 0.031 kg left after 151 years,
C. There will be 0.500 kg left after 151 years.
D. There will be 0.062 kg left after 151 years,

Asuppose a suitcase has a mass of (m) 30 kg and a net force (n) of 10 kg*m/s. what is the acceleration rate of the suitcasein m/s? show your work to support your answer.

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.

How can you increase the strength of an electromagnet?