In an area of the deep ocean, hot magma emerges from a crack in Earth’s crust. Which statement describes what will happen to the seawater above the crack as a result of convection? Water molecules will break apart and flow in a circular pattern.
Water molecules will bond together and rise upward.
The water will become more dense and sink downward.
The water will become less dense and rise upward.

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".