In a wind tunnel experiment the pressure on the upper and lower surfaces of the wings are 0.90`xx 10^(5)` Pa and 0.91 `xx10^(5)`Pa respectively .If the area of the wings is `40 m^(2)` the net lifting force on the wing is

Options

A. `2xx 10^(4)`N
B. `4xx 10^(4)`N
C. `6 xx 10^(4)`N
D. `8 xx 10^(4)`N

Answer

B

Explanation

Pressure differnce which provides the lift
=Pressure difference `xx` Area of the wing
`=(P_(2)xxP_(1))xxA=(0.91xx10^(5)-0.90xx10^(5))Paxx40 m^(2)`
`=0.01xx10^(5) Pa xx 40 m^(2)=4xx10^(4) N`