Which of the following things is an “extended object”? For each item, answer “A” if the item is an acceptable extended object, “B” if the definition of an extended object applies badly to the item, and “D” if it is debatable.
(a) An electron
(b) An atom
(c) A rock
(d) A swarm of bees
(e) The earth’s atmosphere
(f) The water in an ocean current
(g) Sugar molecules dissolved in a cup of water
(h) The vacuum between galaxies
(a) An electron -B
(b) An atom - A
(c) A rock - A
(d) A swarm of bees - D
(e) The earth’s atmosphere - A
(f) The water in an ocean current - B
(g) Sugar molecules dissolved in a cup of water - B
(h) The vacuum between galaxies - B
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Two equal forces are applied to a door. The first force is applied at the midpoint of the door; the second force is applied at the doorknob. Both forces are applied perpendicular to the door. Which force exerts the greater torque?
A) the first at the midpoint B) the second at the doorknob C) both exert equal non-zero torques D) both exert zero torques E) Additional information is needed.
What is the total electric flux through a closed surface containing a 2.0 ?C charge?
a.
b.
c.
d.
e. 0