Dan confirms the authenticity of an amethyst stone by a few tests. during one of the tests, he finds the angle of the refracted ray of light coming out of the amethyst into the air as 28°. if the refractive index of amethyst is 1.55, what is the incident angle?

You are driving to the grocery store at 20 m/s. you are 110m from an intersection when the traffic light turns red. assume that your reaction time is 0.50s and that your car brakes with constant acceleration. how far are you from the intersection when you begin to apply the brakes? what acceleration will bring you to rest right at the intersection? how long does it take you to stop after the light changes? the known values: vi=20m/s xi=110m t=.50s vf=0m/s xf=0m a=?