Air within a piston–cylinder assembly, initially at 30 lbf/in.2, 510°R, and a volume of 6 ft3, is compressed isentropically to a final volume of 1.2 ft3. Assuming the ideal gas model with k = 1.4 for the air, determine the (a) mass, in lb, (b) final pressure, in lbf/in.2, (c) final temperature, in °R, and (d) work, in Btu.

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.