Q1. Ideal gas helium flows through a well-insulated nozzle at stable state. The temperature and velocity at the inlet are 90 °C and 30 m/s, in that order. At the exit, the temperature is -18 °C and the pressure is 3.10 bar. The mass flow rate is 1.25 kg/s. using the ideal gas model, and neglecting potential energy effects, determine the exit area. Take cp, He to be 5.193 kJ/kg·K. Answer in m².

Q2. Two boxes, m1 = 1.0 kg with a coefficient of kinetic friction of 0.10, and m2 = 2.0kg with a coefficient of 0.20, are placed on a plane inclined at 0 = 30o.

(a) What acceleration does each box experience?

(b) If a taut string is connected to the boxes, with m2 at first farther down the slope, what is the acceleration of each box?

(c) If the initial configuration is reversed with m1 starting lower with a taut string, what is the acceleration of each box?