Which of the following is most closely related to the unit of time that humans call the month?

a.

the rotation of the earth once on its axis

b.

the cycle of the moon through all its phases

c.

the rotation of the sun once on its axis

d.

the revolution of the earth once around the sun
never mind found the answer

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".