7-42a 0.5-m3 rigid tank contains refrigerant-134a initially at 200 kpa and 40 percent quality. heat is transferred now to the refrigerant from a source at 35°c until the pressure rises to 400 kpa. determine the entropy change of the refrigerant.

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Coiled springs ought to be very strong and stiff. si3n4 is a strong, stiff material. would you select this material for a spring? explain.

Afluid flows with a velocity field given by v=(x/t)i.. determine the local and convective accelerations when x=3 and t=1.