An object with a mass of 1.5 kg changes its velocity from 15 m/s to 22 m/s during a time interval of 3.5 seconds. what impulse was delivered to the object?

What would occur if the index of refraction of a material was less than n=1? the speed of light would increase to a speed larger than the maximum speed of light in a vacuum. the light wave would not bend at all though the material. the light wave would not be able to refract and would instead reflect off of the material. the speed of light would reduce to values close to 0 m/s.