Wind resistance varies jointly as an object's surface area and velocity. If an mile per hour with a surface area of 25 square feet experiences a wind resistance of 225 Newtons, how fast must a car with 40 square feet of the surface area travel in order to experience a wind resistance of 270 Newtons?

1 answer

w = kav

225 = k(25)(40)

225 = 1000k

k = 9/40

w = 9/40 av

270 = 9/40(40)(v)

270 = 9v

270/9 = v

v = 30 mile per hour