A. Coal is used to primarily to produce and generate electricity and it is responsible for 39 percent of the power supply for the united states.
<span>1) at rest his
weight is 840 N
=> 840N = mass * g => mass = 840 N / g = 840 N / 9.8 m/s^2 = 85.7 kg
2) as the elevator rises, his weight increases to 1050 N,
The reading of the scale is the norma force of it over the body of the person.
And the equation for the force is: Net force = mass * acceleration = normal force - weight at rest
=> mass * acceleration = 1050 N - 840 N = 210 N
acceleration = 210 N / mass = 210 N / 85.7 kg = 2.45 m/s^2 (upward)
3) when the elevator slows to a stop at the 10th
floor, his weight drops to 588 N
=> mass * acceleration = 588 N - 840 N = - 252 N
=> acceleration = - 252 N / 85.71 kg = - 2.94 m / s^2 (downward)
Answer:
Acceleration at the beginning of the trip 2.45 m/s^2 upward
Acceleration at the end of the trip 2.94 m/s^2 downward
</span>
Average velocity = (displacement) / (total time)
Displacement = distance and direction between
the starting point and the end point
The car travels 90 meters north, then 40 meters south.
So it ends up 50 meters north of where it began.
Displacement = 50 meters north
Total time = (15 + 5) = 20 seconds
Average velocity = (50 meters north) / (20 seconds)
= 2.5 m/s north
on touching electroscope gets positively charged, so answer is B. conduction
A
most common source of phosphates in the soil is the weathering of the mineral apatite.
Explanation:
Apatite is a group of phosphate minerals like hydroxylapatite, fluorapatite, and chlorapatite. When apatite rocks weather, they release the phosphate minerals mainly in the form of PO₄ ³⁻ . These minerals become dissolved in water (hydrosphere), where they are readily available to plants and other organisms in the biosphere. The phosphates are taken up and used in biosynthesis. When these organisms die and become buried with sediments, the phosphate gets back to the lithosphere as sedimentary rock.
Learn More:
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