複選題33、 What mechanisms can cause the entropy of a control volume to change? (A) Heat interaction (B) Work interaction (C) Irreversibility (D) Mass flow in or out

10、 In Figure 10, a horizontal force of 500 N acts on a block of weight 1.5 kN placed on an inclined plane. The coefficients of friction between the block and the plane are μs =0.25 andμk = 0.20 . What is the actual frictional force? (A) 200N (B) 500 N (C) 300 N (D) 450 N。