Question 138583
The approximate distance above sea level,d, in kilometres, is given by the formula d= (400(log(P/2)-2.5))/30, where P is the barametric pressure in kilopascals(kPa). What is the barometric pressure 12 kilometres above sea level?
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Substitute 12 for d in the formula
{{{(400(log((P/2))-2.5))/30}}} = 12
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Multiply both sides by 30 to get rid of the denominator
400(log(p/2)) - 2.5 = 30 * 12
:
400(log(p/2)) - 2.5 = 360
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Divide both sides by 400:
log(p/2) - 2.5 = {{{360/400}}}
log(p/2) - 2.5 = .9
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Add 2.5 to both sides:
log(p/2) = .9 + 2.5
log(p/2) = 3.4
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Find 10^x of both sides
{{{p/2}}} = 2511.8864
Multiply both sides by 2
p = 2511.8864 * 2
:
P = 5023.77 kPa
:
:
Check solution on calc; enter:(400(log(5023.77/2)-2.5))/30 = 11.9999 ~ 12