# Drag force (external forced convection)

## Homework Statement

Air at 20kPa and 20°C flows across 5cm diameter cylinder at velocity of 20m/s. Compute the drag force exerted on the cylinder

## Homework Equations

the formula should be use is this, FD = CD*A*den*V^2 / 2
where FD & CD is the drag force and drag coefficient, respectively

## The Attempt at a Solution

i already have density & velocity. my questions are:

1.) im a little confuse (pls dont laugh)..the cylinder is exposed to the flowing air right? or is the air flowing inside the cylinder?

2.) for the area A, based on my references it is the frontal area which is L*D, the length is not given what should i do?

3.) my way in solving for the drag coeff is to solve first for the reynolds number and refer to the figure provided in the book..am i doing it right? is it accurate?

thank you! :)