What two measurements are needed to determine density?

Abox is pushed down at an angle of 32 degrees on a rough surface. the box moves to the right. what equation should be used to find the net force in the y-direction? answers: a. fnet, y = fn - fgb. fnet, y= fp - ffc. fnet, y = fn-fg- fpcos(32)d. fnet, y = fn-fg-fpsin(32)

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.

Which sections of the heating curve illustrate this process?