Sand on a beach is covered by other layers of sand over time. the extra layers compress the first layer, packing it tighter and tighter. over time, the bottom layers of sand have formed into sandstone, with colored bands showing the different layers.
what kind of rock can sandstone be classified as?

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.