A ray moving in water at 55.5 deg

enters plastic, where it bends to

48.7 deg. What is the index of

- refraction for the plastic?

(Water n = 1.33, Air n = 1.00)

(No unit)

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.