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3 years ago

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How can the sun have both a brightness of -26.73 and 4.83? Explain what these numbers mean.

1 answer:

Assoli18 [71]3 years ago

3 0

The Sun has<span> an "absolute magnitude" of </span>4.83 and an "apparent" magnitude of -26.8. (Which is the difference between the numbers). <span>Scientists use what is know as "</span>Absolute" Magnitude<span> to help them understand and compute how bright a star really is. The "</span>absolute" magnitude<span> of an object, such as a star, equals how bright that object would look if it were 10 parsecs, or 32.6 light years away from the Earth.</span>

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Why is the sky blue?

Levart [38]

Answer:

Gases and particles in Earth's atmosphere scatter sunlight in all directions. Blue light is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

7 0

3 years ago

By means of a rope whose mass is negligible, two blocks are suspended over a pulley, as the drawing shows, with m1 = 12.1 kg and

puteri [66]

Answer:

14.8 kg

Explanation:

We are given that

$m_1=43.7 kg$

$m_2=12.1 kg$

$g=9.8 m/s^2$

$a=\frac{1}{2}(9.8)=4.9 m/s^2$

We have to find the mass of the pulley.

According to question

$T_2-m_2 g=m_2 a$

$T_2=m_2a+m_2g=m_2(a+g)=12.1(9.8+4.9)=177.87 N$

$T_1=m_1(g-a)=43.7(9.8-4.9)=214.13 N$

Moment of inertia of pulley= $I=\frac{1}{2}Mr^2$

$(T_2-T_1)r=I(-\alpha)=\frac{1}{2}Mr^2(\frac{-a}{r})=\frac{1}{2}Mr(-4.9)$

Where $\alpha=\frac{a}{r}$

$(177.87-214.13)=-\frac{1}{2}(4.9)M$

$-36.26=-\frac{1}{2}(4.9)M$

$M=\frac{36.26\times 2}{4.9}=14.8 kg$

Hence, the mass of the pulley=14.8 kg

6 0

3 years ago

If you drive 30 miles in 40 minutes, and then 15 miles in 20 minutes, do you have a constant speed?

kompoz [17]

Answer:

A) yes

Explanation:

First section of trip: 30 miles in 40 minutes

Second section of trip: 15 miles in 20 minutes

The formula for speed is distance over time $k=\frac{d}{t}$

Calculate the speeds for each section of the trip.

First:

k = d/t

k = 30miles/40minutes <= reduce fraction by 10 (30÷10 and 40÷10)

k = 3 miles / 4 minutes

Second:

k = d/t

k = 15miles/20minutes <= reduce fraction by 5 (15÷5 and 20÷5)

k = 3 miles / 4 minutes

Therefore there is a constant speed because both sections of the trip are driving at "3 miles / 4 minutes".

3 miles / 4 minutes can be also formatted as:

0.75 miles per minute.

7 0

3 years ago

A piano string having a mass per unit length equal to 4.80 x10^-3 kg/m is under a tension of 1200 N. Find the speed with which a

Travka [436]

Answer:

500m/s

Explanation:

From the question we are given the following;

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v = √1200/0.0048

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Hence the speed at which the wave travels on this string is 500m/s

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3 years ago

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Answer:

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3 years ago