Awooden box weighing 150 n is sliding at a constant rate over a concrete sidewalk. the force required to pull the box at a steady rate is 78 n. what is the coefficient of friction?

a. 1.9
b. 228
c. 72
d. 0.52

Nitrogen (n2) undergoes an internally reversible process from 6 bar, 247°c during which pν1.2 = constant. the initial volume is 0.1 m3 and the work for the process is 121.14 kj. assuming ideal gas behavior, and neglecting kinetic and potential energy effects, determine heat transfer, in kj, and the entropy change, in kj/s. show the process on a t-s diagram.