A20-kg wagon accelerates on a horizontal surface at 0.50 m⁄s2 when pulled by a rope exerting a 120-n force on the wagon at an angle of 25° above the horizontal. determine the magnitude of the effective friction force exerted on the wagon and the effective coefficient of friction associated with this force.

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)