Explanation:
Given that,
Weight = 280 lbs
Height = 60 ft
Power = 3.50 hp
(a). We need to calculate the work done by the boom on the fireman
Using formula of work done


Put the value into the formula




The work done by the boom is 21.59 Btu.
(b). We know that,
1 hp = 550 ft lbf
So, 

We need to calculate the time
Using formula of time

Put the value into the formula


The time is 8.7 sec.
Hence, This is the required solution.
C) accretionary-wedge complex.
Explanation:
The accretionary wedge complex is a thick accumulation of sediments and small tectonic blocks formed from materials scraped off subducting oceanic lithosphere at a convergent margin.
Space between the subducting plate and the less dense plate gets filled by sediments scraped off the subducting plate and this forms a wedge like sediment called the accretionary wedge.
- The accretionary wedge is invariably made up of materials found on the ocean floor.
- Under extreme conditions, some parts of wedge transforms into metamorphic rocks.
- The wedge is made up of: pelagic sediments, ocean floor basalts e.t.c
Learn more:
Sedimentary rocks brainly.com/question/9131992
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Answer:
The correct answer is 
Explanation:
The formula for the electron drift speed is given as follows,

where n is the number of of electrons per unit m³, q is the charge on an electron and A is the cross-sectional area of the copper wire and I is the current. We see that we already have A , q and I. The only thing left to calculate is the electron density n that is the number of electrons per unit volume.
Using the information provided in the question we can see that the number of moles of copper atoms in a cm³ of volume of the conductor is
. Converting this number to m³ using very elementary unit conversion we get
. If we multiply this number by the Avagardo number which is the number of atoms per mol of any gas , we get the number of atoms per m³ which in this case is equal to the number of electron per m³ because one electron per atom of copper contribute to the current. So we get,

if we convert the area from mm³ to m³ we get
.So now that we have n, we plug in all the values of A ,I ,q and n into the main equation to obtain,

which is our final answer.
Ca(NO3)2(aq) + Na2CO3(aq) → 2NaNO3 + CaCO3⬇. NaNO3 is solution so CaCO3 is the precipitate formed.
Answer:
f = 1 m
Explanation:
The magnification of the lens is given by the formula:

where,
M = Magnification = 4
q = image distance = 5 m
p = object distance = ?
Therefore,

Now using thin lens formula:

<u>f = 1 m</u>