Question

The drag force, Fd, imposed by the surrounding air on a

Answer 1

Answer:

a)  23.551 hp

b)  516.89 hp

Explanation:

given:

$F_{d} =\frac{1}{2} C_{d} A_{p} V^{2} \\V_{a}=25 m/hr-->25*\frac{5280}{3600} =36.67ft/s\\V_{b}=70 m/hr-->70*\frac{5280}{3600} =102.67ft/s\\\\C_{d}=.28\\A=25 ft^2\\p=.075lb/ft^2$

required:

the power in hp

solution:

$(F_{d})_{a} =\frac{1}{2} C_{d} A_{p} V_{a} ^{2}$.............(1)

by substituting in the equation (1)

         =353.27 lbf

$(F_{d})_{b} =\frac{1}{2} C_{d} A_{p} V_{b} ^{2}$..........(2)

by substituting in the equation (2)

         = 2769.29 lbf

power is defined by

             P=F.V

     $P_{a}=$353.27*36.67

           =12954.411 lbf.ft/s

           =12954.411*.001818

           =23.551 hp

      $P_{a}=$2769.29*102.67

           = 284323 lbf.ft/s

           = 284323*.001818

           = 516.89 hp