A 2.8 kg rectangular air mattress is 2.00 m long, 0.500 m wide, and

1 answer:

8 0

First off, we have to assume that the 2.8 kg mass of the air matress includes both the material that the matress is constructed from and the air that is contained within.

The mattress can support a total weight that is equal to the weight of water that the air matress displaces.

The volume of the air mattress is:

V(mattress) = (2 m)(0.5 m)(0.1 m) = 0.1 m³

This volume is equal to the maximum amount of water that the matress can displace in the water before it begins sinking.

The density of water is 1000 kg / m²

The weight of the maximum amount of displaced water is:

V(matress) * (density of water) * (g) = (0.1 m³) * (1000 kg / m³) * (9.81 m / s²) = 981 N.

Let m represent the mass that the matress is supporting.

The total weight of the matress and the supported mass is:

(2.8 + m) * 9.81

Setting this weight equal to the weight of the water displaced gives:

(2.8 + m) * 9.81 = 981

2.8 + m = 100

m = 100 - 2.8

m = 97.2 kg

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1. A piece of metal weighs 50.0 N in air, 36.0 N in water, and 41.0 N in an unknown

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Answer:

a) 3.37 x $10^{3} kg/m^3$

b) 6.42kg/ $m^{3}$

Explanation:

a) Firstly we would calculate the volume of the metal using it`s weight in air and water , after finding the weight we would find the density .

Weight of metal in air = 50N = mg implies the mass of metal is 5kg.

Now the difference of weight of the metal in air and water = upthrust acting on it = volume (metal) p (liquid) g = V (1000)(10) = 14N. So volume of metal piece = 14 x $10^{-4}$ $kg/m^{3}$ . So density of metal = mass of metal / volume of metal = 5 / 14 x $10^{-4}$ $kg/m^{3}$ = 3.37 x $10^{3} kg/m^3$

b) Water exerts a buoyant force to the metal which is 50−36 = 14N, which equals the weight of water displaced. The mass of water displaced is 14/10 = 1.4kg Since the density of water is 1kg/L, the volume displaced is 1.4L. Hence, we end up with 3.57kg/l. Moreover, the unknown liquid exerts a buoyant force of 9N. So the density of this liquid is 6.42kg/ $m^{3}$

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2 years ago

During an early phase of the planet's existence, earth's atmosphere was similar in composition to the atmospheres of mars and ve

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The answer is carbon dioxide. This primordial earths’ atmosphere was composed by gasses from degassing of the earth's interior after its formation. It is after the beginning of life that oxygen levels began to rise and levels of carbon dioxide began to reduce in the atmosphere (as a result of photosynthesis).

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3 years ago

Several forces act on an object at rest. It is known that the sum of the forces acting on the object is zero. Which statement is

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Answer:

When net force of zero acting on a ball which is at rest , then the object center of mass will not accelerate , but the object may begin to rotate .

Explanation:

Here when there is an object where several forces are acing upon are zero then the center of mass will not accelerate because we know that

$A_{com}=\frac{F_{net}}{M}$