Select the correct answer.
and
consider four objects: a, b, c, and d. if a is negatively charged and b and c attract a but repel each other, what is the charge on
a.
both b and c are positively charged.
b.
both b and c are negatively charged.
c.
b is positively charged and c is negatively charged.
d.
bis negatively charged and c is positively charged.
e.
both b and c have no charge.

Apulley with a mechanical advantage of 5 will require you to pull times the amount of rope. a. 1/5 b. 5 c. 10 d. 15

Part f - example: finding two forces (part i) two dimensional dynamics often involves solving for two unknown quantities in two separate equations describing the total force. the block in (figure 1) has a mass m=10kg and is being pulled by a force f on a table with coefficient of static friction îľs=0.3. four forces act on it: the applied force f (directed î¸=30â above the horizontal). the force of gravity fg=mg (directly down, where g=9.8m/s2). the normal force n (directly up). the force of static friction fs (directly left, opposing any potential motion). if we want to find the size of the force necessary to just barely overcome static friction (in which case fs=îľsn), we use the condition that the sum of the forces in both directions must be 0. using some basic trigonometry, we can write this condition out for the forces in both the horizontal and vertical directions, respectively, as: fcosî¸â’îľsn=0 fsinî¸+nâ’mg=0 in order to find the magnitude of force f, we have to solve a system of two equations with both f and the normal force n unknown. use the methods we have learned to find an expression for f in terms of m, g, î¸, and îľs (no n).

Geologists get to play with chemistry, physics, and history! and what a history you will meet as youwork your way through the course. starting at the beginning, the textbook provides the scientifically acceptedstart of the and promises that you'll get to explore some of the evidence for that scientific view, later inthe semester. meanwhile, which is more nearly correct of the scientifically accepted view? a) the earth formed when the big bang caused older materials to fall together, about 14 billion years ago.b) the earth formed from the falling together of older materials, about 4.6 billion years ago.c) the earth formed in the big bang, about 6000 years ago.d) the earth is eternal, having been here forever and promising to be here forever.e) the earth was assembled by gigantic space beavers, which gnawed down the primordial tree of life andpiled its branches together to form the planet.