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3 years ago

There are 640 acres in a square mile. how many square meters are there in 7.80 acres.

Physics

1 answer:

lukranit [14]3 years ago

8 0

Answer:

On 7.8 acres there are 31565.3 square meters

7.8 acres = 31565.3 m²

Explanation:

Conceptual analysis

Acre, square mile and square meter are area units, so their equivalences are in square units.

Known data

1 (mi)² = 640 acres

1 mi = 1609.34 m

Problem development

We know that 1 mile = 1609.34m, then: (1 mile)² = (1609.34m)²=(1609.34)²m²

We apply the known conversion factors to calculate the square meters (X) in 7.8 acres:

$X=7.8 acres *\frac{(1 mi)^{2} }{640 acres} * \frac{(1609.34)^{2}m^{2} }{(1 mi)^{2} }$

We eliminate acres and square miles (mi²) because they are in the numerator and denominator, so the answer is in square meters (m²)

X=31565.3 m²

On 7.8 acres there are 31565.3 square meters

7.8 acres = 31565.3 m²

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1) Data given

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100-20= 80% of the block volume is submerged

2) Notation

mb= mass of the block

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mw = mass water displaced

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3) Forces involved (part a)

For this case we have two forces the buoyant force (B), defined as the weight of water displaced acting upward and the weight acting downward (W)

Since we have an equilibrium system we can set the forces equal. By definition the buoyant force is given by :

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If we solve for mw we got $m_w = \rho_w V_w$ (2)

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And solving for V we have

V = (mg)/(0.8 ρ_w g )

We cancel the g in the numerator and the denominator we got

V = (m)/(0.8 ρ_w)

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For this case we have bricks above the block, and we want the maximum mass for the bricks without causing it to sink below the water surface.

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And finding the mass fro the definition of weight we have

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