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AP® Physics 1 & 2

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Force on Roof

APPH12-I0O11X

The air inside a certain building is still, while air moves over the flat, horizontal roof of the building at a speed of $10\text{ m/s}$. The density of the air is approximately $1 \text{ kg/m}^{ 3 }$, the roof has a surface area of $2{,}000 \text{ m}^{ 2 }$, and the roof can be considered to have negligible thickness.

Which one of the following is closest to the net force on the roof due only to air pressure?

A

$50 \text{ N}$ upward

B

$50 \text{ N}$ downward

C

$100{,}000 \text{ N}$ upward

D

$100{,}000 \text{ N}$ downward