A 15-ft3 tank contains oxygen initially at 14.7 psia and 80°F. A paddle wheel within the tank is rotated until the pressure inside rises to 20 psia. During the process 20 Btu of heat is lost to the surroundings. Determine the paddle-wheel work done. Neglect the energy stored in the paddle wheel. The gas constant and molar mass of oxygen are R = 0.3353 psia·ft3/lbm·R and M = 32 lbm/lbmol. The specific heat of oxygen at the average temperature of Tavg = (735 + 540)/2 = 638 R is cv ,avg= 0.160 Btu/lbm·R.

Apositive rod is placed to the left of sphere a, and the spheres are separated. which best describes the spheres? sphere a is negative and sphere b is positive because protons from sphere a are attracted to the rod and move to sphere b. sphere a is negative and sphere b is positive because electrons from sphere b are attracted to the rod and move to sphere a. sphere a is positive and sphere b is negative because electrons from the rod move to sphere b and protons then move to sphere a. sphere a is positive and sphere b is negative because protons move from sphere b to the rod and also to sphere a.

A5 nc point charge is at the origin and a second 3 nc point charge is on the x-axis at x = 0.8 m. find the magnitude and direction of the electric field on the x-axs at x = 0.2 m. you may express the direction by letting positive field mean the positive x direction

If a refrigerator is a heat pump that follows the first law of thermodynamics, how much heat was removed from food inside of the refrigerator if it released 380j of energy to the room?