The drag force, Fd, imposed by the surrounding air on a
vehicle moving with velocity V is given by
Fd 5 CdA12
rV2
where Cd is a constant called the drag coefficient, A is the
projected frontal area of the vehicle, and r is the air density.
Determine the power, in hp, required to overcome aerodynamic
drag for an automobile moving at (a) 25 miles per hour,
(b) 70 miles per hour. Assume Cd 5 0.28, A 5 25 ft2, and r 5
0.075 lb/ft2.

Liquid flows at steady state at a rate of 2 lb/'s through a pump, which operates to raise the elevation of the liquid 100 ft from control volume inlet to exit. the liquid specific enthalpy at the inlet is 40.09 btu/lb and at the exit is 40.94 btub. the pump requires 3 btu/s of power to operate. if kinetic energy effects are negligible and gravitational acceleration is 32.174 tt/s, the heat transfer rate associated with this steady state process is most closely 1)-2,02 btu/s from the liquid to the surroundings 2)-3.98 btu/s from the surroundings to the liquid. 3)-4.96 btu/s from the surroundings to the liquid. 4)-1.04 btu/s from the liquid to the surroundings.