Answer:
Physical science is the study of the inorganic world. That is, it does not study living things. (Those are studied in biological, or life, science.) The four main branches of physical science are astronomy, physics, chemistry, and the Earth sciences, which include meteorology and geology.
Explanation:
The answer is B
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Sigma F.dS = total work done = change in kinetic energy
(220, 320, -120).(18-13,-11+19,-8+3) +(<span>150, 230, 220).(22-18,-17+11,-3+8)= 1/2 *60*(V^2- 3.5^2)
220*5+320*8+ -120*-5 + 150*4 + 230* 6 +220* -5= ..
simplify his
</span>
Work is force times
distance. <span>
The distance is 1.3 m/s x 7.6 s = 9.88 m </span>
<span>
the force is only sufficient force to overcome friction.
Assuming the table is a level table, the force to overcome friction is µ x
normal force = 0.6 x (12 kg) x 9.8 m/s^2 = 70.56 N </span>
<span>
So the work is 70.56 N x 9.88 m = 697.13 J
<span>The power is simply the work / time = 697.13 J / 7.6 s = 91.7
or 92 Watts </span></span>
Motion must be defined relative to something.
Here's an obvious, everyday example:
-- You're in a passenger jet, going to visit grandma on the
coast for the holidays.
-- You're sitting still in your seat, listening to some 'mp3's,
reading a book, and dozing off.
-- At the same time, people on the ground see you flying over
at almost 500 miles per hour.
Are you moving at 500 mph, or are you not moving at all ?
The answer is 'Yes. Both.'. It just depends on who's measuring your speed.
There's no such thing as your "real" speed. Motion is always
relative to something. Different reference = different speed.