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Assuming that the Earth is a sphere of radius 6378 km: (i) Find the length of the equator, correct to the nearest km - Leaving Cert Mathematics - Question b - 2015

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Assuming that the Earth is a sphere of radius 6378 km: (i) Find the length of the equator, correct to the nearest km. (ii) Find the volume of the Earth in the form... show full transcript

Worked Solution & Example Answer:Assuming that the Earth is a sphere of radius 6378 km: (i) Find the length of the equator, correct to the nearest km - Leaving Cert Mathematics - Question b - 2015

Step 1

Find the length of the equator, correct to the nearest km.

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Answer

The length of the equator can be calculated using the formula for the circumference of a circle:

C=2πrC = 2 \pi r

Substituting the radius of the Earth (6378 km):

C=2×π×637840074.15 kmC = 2 \times \pi \times 6378 \approx 40074.15 \text{ km}

Rounding to the nearest km, the length of the equator is approximately 40074 km.

Step 2

Find the volume of the Earth in the form $a \times 10^{n}$, where $1 \leq a < 10$ and $n \in \mathbb{N}$.

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Answer

To find the volume of a sphere, the formula is:

V=43πr3V = \frac{4}{3} \pi r^{3}

Substituting the radius:

V=43π(6378)31.0867×1012 km3V = \frac{4}{3} \pi (6378)^{3} \approx 1.0867 \times 10^{12} \text{ km}^3

Thus, the volume of the Earth can be expressed as:

V1.087×1012 km3V \approx 1.087 \times 10^{12} \text{ km}^3

Rounding to three decimal places, we find:

a=1.087a = 1.087

Step 3

How many times greater than the mass of the Earth is the mass of Sun?

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Answer

To find how many times greater the mass of the Sun is than the mass of the Earth, we use the following equation:

Number of times=Mass of SunMass of Earth\text{Number of times} = \frac{\text{Mass of Sun}}{\text{Mass of Earth}}

Substituting the masses:

Number of times=1.99×10305.97×1024333.333\text{Number of times} = \frac{1.99 \times 10^{30}}{5.97 \times 10^{24}} \approx 333.333

Rounding to the nearest whole number, we find it is approximately 333.

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