Answer:
Power = 21[W]
Explanation:
Initial data:
F = 35[N]
d = 18[m]
In order to solve this problem we must remember the definition of work, which tells us that it is equal to the product of a force for a distance.
Therefore:
Work = W = F*d = 35*18 = 630 [J]
And power is defined as the amount of work performed in a time interval.
Power = Work / time
Time = t = 30[s]
Power = 630/30
Power = 21 [W]
A. freezing, when water turns to ice the water is turning from a liquid to a solid.
Answer:
b) 472HZ, 408HZ
Explanation:
To find the frequencies perceived when the bus approaches and the train departs, you use the Doppler's effect formula for both cases:

fo: frequency of the source = 440Hz
vs: speed of sound = 343m/s
vo: speed of the observer = 0m/s (at rest)
v: sped of the train
f: frequency perceived when the train leaves us.
f': frequency when the train is getTing closer.
Thus, by doing f and f' the subjects of the formulas and replacing the values of v, vo, vs and fo you obtain:

hence, the frequencies for before and after tha train has past are
b) 472HZ, 408HZ
Answer:
This property could be used to create technologically-advanced tools or machines that could easily locate the mineral deposits.
Explanation:
Mineral deposits are hard to find, unless you have the skill or the proper tools in locating them. This is the reason why many people are mining in order to explore the different areas where they could find these deposits.
If one would consider the property of minerals, such as being good conductors of heat and electricity,<u> then they could create a tool or machine that would aid in their exploration.</u> Inventors could probably come up with a sensitive detector which signals when it reaches an area of high heat and electric conductivity. Since most minerals such as <em>gold, silver, copper, galena, bornite </em>and the like have this property, then miners will have a lesser amount of time looking for them.
If this technology will be implemented, though, regulation policy must be strictly implemented because it might lead to<em> over-mining</em> thus leading to the depletion of mineral deposits.