When running outside, there is a drag force due to the runner moving through the air. A certain runner experiences a drag force with magnitude Fd=(0.3kg/m3 ) x v2 when running.

a. If the runner has a cross-sectional area of 1/5m2 , what is her drag coefficient? The density of air is 1/2kg m3 .

b. If the runner has a mass of 56kg and is running outside at 4m/s, find the drag force she experiences.