Which statement best describes the relationship between an object's density and its index of refraction? As the tendency of the atoms to absorb energy before remitting it increases, the refractive index increases.

As the physical density of the substance increases, the refractive index increases.

As the mass per unit volume of the substance increases, the refractive index decreases.

As the optical density increases, the refractive index decreases

Atruck going 15 kmôź°€h has a head-on collision with a small car going 30 kmôź°€h. which statement best describes the situation? (a) the truck has the greater change of momentum because it has the greater mass. (b) the car has the greater change of momentum because it has the greater speed. (c) neither the car nor the truck changes its momentum in the collision because momentum is conserved. (d) they both have the same change in magnitude of momentum because momentum is conserved. (e) none of the above is necessarily true. 2. a small boat coasts at constant speed under a bridge. a heavy sack of sand is dropped from the bridge onto the boat. the speed of the boat (a) increases. (b) decreases. (c) does not change. (d) without knowing the mass of the boat and the sand, we can’t tell.