# Homework Help: Calculating how to overcome drag

1. Sep 22, 2009

### rosie_burk

1. The problem statement, all variables and given/known data

Studetns examine the aerodynamics of a model car which has a drag force in air of 10 N at 10 m/s.

They wish to estimate what the drag will be for a full scale model, and the energy lost on a given trip. The drag coefficient C remains constant C= 0.6. The cross-sectional area A of the car is increased to 2 times its original area, and the speed is now increased to 20 m/s.
How much work does this car do in overcoming air resistance in a journey of 1000 m. Answer in joule.

2. Relevant equations

new drag force = (C/0.5) * (area/original area)* original drag force
then Energy to overcome drag = Work = force x distance.

3. The attempt at a solution

(.6*.5)(20/10)(10)=24

24*1000=2400

$$\frac{F_{1}}{F_{2}} = \frac{A_{1} v_{1}}{A_{2} v_{2}}$$