Emma sets up an experiment to study light passing through different materials. What does Emma observe happen to light at the point when it passes into a material where the speed of light changes? A. the light is brighter
B. the light is absorbed
C. the light is refracted
D. the light is reflected
D.

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.