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3 years ago

According to astronomers, what is a "light year" answer key

1 answer:

3 0

A light-year is defined as the distance the light can cover in one year.

The light travels at speed of $c=3 \cdot 10^8 m/s$ , and one year converted into seconds is
$1 y = 365 \frac{d}{y} \cdot 24 \frac{h}{d} \cdot 60 \frac{m}{h} \cdot 60 \frac{s}{m}=3.15 \cdot 10^7 s$

So the distance covered by the light in one year is
$S=vt =(3 \cdot 10^8 m/s)(3.15 \cdot 10^7 s)=9.45 \cdot 10^{15} m$
And this is the distance that corresponds to one light-year.

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4. During a 12- hour period, the temperature dropped 48°. How many degrees did the temperature drop each hour.

uranmaximum [27]

Answer:

-4

Step-by-step explanation:

3 0

3 years ago

Which equations represent the line that is parallel to 3x − 4y = 7 and passes through the point (−4, −2)? Select two options.

Elanso [62]

Answer:

2 and 5

Step-by-step explanation:

The slope-intercept form of a line is y=mx-b where m is slope and b is y-intercept.

The point-slope form of a line is y-y1=m(x-x1) where m is the slope and (x1,y1) is a point on the line.

The standard form a line is ax+by=c.

So anyways parallel lines have the same slope.

So if we are looking for a line parallel to 3x-4y=7 then we need to know the slope of this line so we can find the slope of our parallel line.

3x-4y=7

Goal: Put into slope-intercept form

3x-4y=7

Subtract 3x on both sides:

-4y=-3x+7

Divide both sides by -4:

$y=\frac{-3}{-4}x+\frac{7}{-4}$

Simplify:

$y=\frac{3}{4}x+\frac{-7}{4}$

So the slope of this line is 3/4. So our line that is parallel to this one will have this same slope.

So we know our line should be in the form of $y=\frac{3}{4}x+b$ .

To find b we will use the point that is suppose to be on our new line here which is (x,y)=(-4,-2).

So plugging this in to solve for b now:

$-2=\frac{3}{4}(-4)+b$

$-2=-3+b$

$3-2=b$

$b=1$

so the equation of our line in slope-intercept form is $y=\frac{3}{4}x+1$

So that isn't option 1 because the slope is different. That was the only option that was in slope-intercept form.

The standard form of a line is ax+by=c and we have 2 options that look like that.

So let's rearrange the line that we just found into that form.

$y=\frac{3}{4}x+1$

Clear the fractions because we only want integer coefficients by multiplying both sides by 4.

This gives us:

$4y=3x+4$

Subtract 3x on both sides:

$-3x+4y=4$

I don't see this option either.

Multiply both sides by -1:

$3x-4y=-4$

I do see this as a option. So far the only option that works is 2.

Let's look at point slope form now.

We had the point that our line went through was (x1,y1)=(-4,-2) and the slope,m, was 3/4 (we found this earlier).

y-y1=m(x-x1)

Plug in like so:

y-(-2)=3/4(x-(-4))

y+2=3/4 (x+4)

So option 5 looks good too.

7 0

3 years ago

Read 2 more answers

Write a function rule that represents D less than five is P

GarryVolchara [31]

the answer is

p = 5 - d

4 0

3 years ago

Brandon says to get that shade of green, 6 pints of yellow paint need to be added to the bucket. Bianca says that won't work. In

Ksenya-84 [330]

<span>There are 2 pints of blue and 2 pints of yellow in the bucket.
To be 80% yellow, the new color will be (100%-80%=) 20% blue.

2 pints is 20% of (2 pints/0.20=) 10 pints.
With 4 pints in the bucket, to make 10 pints you should add
(10 pints-4 pints=) 6 more pints of yellow paint.

ANSWER: You should add 6 pints of yellow to the 4 pints of green in the bucket to make the new color that is 80% yellow.</span>

3 0

3 years ago

If my diameter is 19 inches what is my radius

Masja [62]

Answer:

Step-by-step explanation:

To find the radius of a circle you multiply the diameter by 38

(to find the diameter, you divide the radius by 2)

4 0

3 years ago