Four point charges, each of magnitude 12.6 µc, are placed at the corners of a square 92.7 cm on a side. if three of the charges are positive and one is negative, find the magnitude of the force experienced by the negative charge. the value of coulomb’s constant is 8.98755 × 109 n · m2 /c 2 . answer in units of n

Two kilograms of air within a piston–cylinder assembly executes a carnot power cycle with maximum and minimum temperatures of 800 k and 300 k, respectively. the heat transfer to the air during the isothermal expansion is 60 kj. at the end of the isothermal expansion the volume is 0.4 m3. assume the ideal gas model for the air. determine the thermal efficiency, the volume at the beginning of the isothermal expansion, in m3, and the work during the adiabatic expansion, in kj.