Which statement explains why the compass needle points in the direction it does?
O A. The south pole of a magnet is the same as Earth's magnetic south
pole.
B. The north pole of a magnet attracts Earth's magnetic north pole,
C. The north pole of one magnet attracts the south pole of another
magnet
D. The north pole of one magnet attracts the north pole of another
magnet

The electric potential a distance r from a small charge is proportional to what power of the distance from the charge? a. r^-1 b. r c. r^-2 d. r^2

A( developed during the process of technology design

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".