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2 years ago

5

If the distance to a distant galaxy is recorded as 10,000 light years, then light must have been traveling for 5000 years to rea

ch the Earth.
True or false
Pls Help! first reply will get brainliest

2 answers:

satela [25.4K]2 years ago

5 0

False false false false

Yuri [45]2 years ago

4 0

False is the correct answer

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Elena earns $10.50 per hour as a server working x hours per week. She also earns $8.50 per hour editing poetry for y hours per w

klasskru [66]

Answer:

Option A: Elena can work as a server for 5 hours and edit poetry for 10 hours.

Explanation:

We are given the system of linear inequalities modeling this situation as; 10.50x + 8.50y ≥ 125

x + y ≤ 17

Where;

x represents number of server working hours per week.

y represents number of editing poetry hours per week.

In option A, x = 5 and y = 10. Let's plug them both into the first equation;

10.50(5) + 8.50(10) ≥ 125

Left hand side gives 137.5. So it fulfills the inequality.

Repeating the same for the 2nd equation, we have;

5 + 10 ≤ 17

Left hand side is 15 and it fulfills the equation. Option A is correct.

In option B, x = 10 and y = 9. Let's plug them both into the first equation;

10.50(10) + 8.50(9) ≥ 125

Left hand side gives 181.5. So it fulfills the inequality.

Repeating the same for the 2nd equation, we have;

10 + 9 ≤ 17

Left hand side is 17 and it doesn't fulfill the inequality. Option B is wrong.

In option C, x = 10 and y = 1. Let's plug them both into the first equation;

10.50(10) + 8.50(1) ≥ 125

Left hand side gives 113.5. So it doesn't fulfill the inequality.

Option C is wrong.

In option D, x = 3 and y = 10. Let's plug them both into the first equation;

10.50(3) + 8.50(10) ≥ 125

Left hand side gives 116.5. So it doesn't fulfill the inequality.

Option D is wrong.

5 0

3 years ago

A 59.3 kg diver jumps off a board

ser-zykov [4K]

The board is 2.50m high.

Why?

We can calculate how high was the board applying the Law of Conservation of Mechanical Energy. This Law states that the mechanical energy (kinematic and potential) will be conserved during the motion.

It can be described with the following formula:

$E_{M_{1}}=E_{M_{2}}\\\\PE_{1}+KE_{1}=PE_{2}+KE_{2}$

$PE=m*g*h\\KE=\frac{1}{2}m*v^{2}$

At the top of the boar, the kinetic energy is equal to 0.

At the water, the potential energy is equal to 0.

So,

$PE_{1}=KE_{2}\\\\m*g*h=1450J\\\\59.3kg*9.8\frac{m}{s^{2}}*h=1450J\\ \\h=\frac{1450J}{59.3kg*9.8\frac{m}{s^{2}}}=2.50m$

Hence, we have that the board is 2.50m high.

Have a nice day!

6 0

3 years ago

Find the frequency, if the amplitude of a 3000g object in simple harmonic motion is 1000cm and the maximum speed of the object i

Oksana_A [137]

Answer:

A = 10 m amplitude

m = 3 kg mass of object

Vm = 5 m/s

w A = Vm where w = omega

w = 2 * pi * f

2 * pi * f 10 = 5

f = 5 / (20 * pi) = .0796 / sec

7 0

2 years ago

A hiker walks 200 m west and then walks 100 m north. In what direction is her resulting displacement?a. northb. westc. northwest

emmainna [20.7K]

Answer:

Option (C) is correct.

Explanation:

Assuming that the hiker starts walking from the origin O as shown in the figure.

First, he walks 200 m west to point A (say), then he walks 100 m north to the final point B (say) as shown in the figure.

The final point B is in the north-west direction, therefore, the resulting point is in the north-west direction.

Hence, option (C) is correct.

7 0

3 years ago

a stone is thrown horizonttaly from a cliff of a hill with an initial velocity of 30m/s it hits the ground at a horizontal dista

ELEN [110]

Answer:

a) Time = 2.67 s

b) Height = 35.0 m

Explanation:

a) The time of flight can be found using the following equation:

$x_{f} = x_{0} + v_{0_{x}}t + \frac{1}{2}at^{2}$ (1)

Where:

$x_{f}$ : is the final position in the horizontal direction = 80 m

$x_{0}$ : is the initial position in the horizontal direction = 0

$v_{0_{x}}$ : is the initial velocity in the horizontal direction = 30 m/s

a: is the acceleration in the horizontal direction = 0 (the stone is only accelerated by gravity)

t: is the time =?

By entering the above values into equation (1) and solving for "t", we can find the time of flight of the stone:

$t = \frac{x_{f}}{v_{0}} = \frac{80 m}{30 m/s} = 2.67 s$

b) The height of the hill is given by:

$y_{f} = y_{0} + v_{0_{y}}t - \frac{1}{2}gt^{2}$

Where:

$y_{f}$ : is the final position in the vertical direction = 0

$y_{0}$ : is the initial position in the vertical direction =?

$v_{0_{y}}$ : is the initial velocity in the vertical direction =0 (the stone is thrown horizontally)

g: is the acceleration due to gravity = 9.81 m/s²

Hence, the height of the hill is:

$y_{0} = \frac{1}{2}gt^{2} = \frac{1}{2}9.81 m/s^{2}*(2.67 s)^{2} = 35.0 m$

I hope it helps you!

5 0

3 years ago