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4 years ago

7

Calculate the energy in kilowatt hours used by a heater that operates continuously for 30 minutes. The heater has a power rating

of 3000 W.

1 answer:

maria [59]4 years ago

5 0

3kW X 0.5hours
= 1.5 kWh

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What is the cause of weathering

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Plant and animal life, atmosphere and water are the major causes of weathering .

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3 years ago

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The Pacific Plate is moving 29 mm/year toward the north and 20 mm/year toward the west relative to the North American Plate. Sho

adell [148]

Answer:

7 mm per year

Explanation:

It is given that :

The Pacific plate is moving towards north at = 29 mm per year

The Pacific plate is moving towards west at = 20 mm per year

We have to calculate the total relative motion towards the northwest.

So we have to find the resultant of the two motions.

Since the two movements are perpendicular, therefore the angle between the two motions is 90 degree.

Therefore, finding their resultant,

$R^2=(29)^2+(20)^2$

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R = 7

Therefore, total relative motion towards the northwest is 7 mm per year.

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3 years ago

How is the earth a cracked hard boiled egg

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3 years ago

The most basic difference between elliptical galaxies and spiral galaxies is that ________.

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4 years ago

A newly discovered element has two isotopes. One has an atomic weight of 120.9038 amu with 57.25% abundance. The other has an at

Katarina [22]

Answer : The atomic weight of the element is, 121.75 amu

Explanation :

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

$\text{Average atomic mass }=\sum_{i=1}^n\text{(Atomic mass of an isotopes)}_i\times \text{(Fractional abundance})_i$

As we are given that,

Mass of isotope 1 = 120.9038 amu

Percentage abundance of isotope 1 = 57.25 %

Fractional abundance of isotope 1 = 0.5725

Mass of isotope 2 = 122.8831 amu

Percentage abundance of isotope 2 = 100 - 57.25 = 42.75 %

Fractional abundance of isotope 2 = 0.4275

Now put all the given values in above formula, we get:

$\text{Average atomic mass of element}=\sum[(120.9038\times 0.5725)+(122.8831\times 0.4275)]$

$\text{Average atomic mass of element}=121.75amu$

Therefore, the atomic weight of the element is, 121.75 amu

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3 years ago