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3 years ago

To calculate the dashed orbits from the stellar positions, astronomers had to assume that __________.

1 answer:

3 0

Here is the answer that would best complete the given statement above. To calculate the dashed orbits from the stellar positions, astronomers had to assume that if they observed for many more years, the dots would trace out ellipses. Hope this is the answer that you are looking for.

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PLEASE HELP!!!!!

never [62]

Answer:

The answer is A

Explanation:

When a rockets thrusters push on the ground the ground pushes back on the rocket with equal force in the opposite direction. Hence the rocket takes off.

Newtons third law of motion states, for every action there is an equal and opposite reaction.

7 0

2 years ago

A concert loudspeaker suspended high off the ground emits 34 W of sound power. A small microphone with a 1.0 cm2 area is 44 m fr

rjkz [21]

Answer:

Part A

I = 1.4 mW/m²

Part B

β = 91.46 dB

Explanation:

Part A

Sound intensity is the power per unit area of sound waves in a direction perpendicular to that area. Sound intensity is also called acoustic intensity.

For a spherical sound wave, the sound intensity is given by;

$I = \frac{P}{A}$

$I = \frac{P}{4\pi r^{2}}$

Where;

P is the source of power in watts (W)

I is the intensity of the sound in watt per square meter (W/m2)

r is the distance r away

Given:

P = 34 W,

A = 1.0 cm²

r = 44 m

The sound intensity at the position of the microphone is calculated to be;

$I = \frac{34}{4\pi (44)^{2}}$

I = 0.0013975 W/m²

≈ I = 0.0014 W/m² = 1.4 × 10⁻³ W/m²

I = 1.4 mW/m²

The sound intensity at the position of the microphone is 1.4 mW/m².

Part B

Sound intensity level or acoustic intensity level is the level of the intensity of a sound relative to a reference value. It is a a logarithmic quantity. It is denoted by β and expressed in nepers, bels, or decibels.

Sound intensity level is calculated as;

β $= 10log_{10}\frac{I}{I_{0}}$ dB

Where,

β is the Sound intensity level in decibels (dB)

I is the sound intensity;

I₀ is the reference sound intensity;

By pluging-in, I₀ is 1.0 × 10⁻¹² W/m²

∴ β $= 10log_{10}\frac{1.4 * 10^{-3} W/m^{2}}{1.0 * 10^{-12} W/m^{2}}$

β $= 10log_{10} (1.4 * 10^{9})$

β = 91.46 dB

The sound intensity level at the position of the microphone is 91.46 dB.

4 0

3 years ago

Kissa and Lily ran a race in gym class Lily was off balance so she did not start until 2 seconds had passed

Paul [167]

Average speed = (distance covered) / (time to cover the distance)

Tissa covered 60 meters in 10 seconds. Her average speed was

(60 m) / (10 sec) = 6 m/s.

That's the slope of the dotted line.

Lilly covered 60 meters in 8 seconds. Her average speed was

(60 m) / (8 sec) = 7.5 m/s .

That's the slope of the solid line.

Lilly covered the same distance in less time, and both girls
arrived at the finish line together. Technically, in science talk,
we would say that Lilly ran "faster", and her average speed
was "greater".

We can detect that by looking at the graph, because Lilly's line
has the characteristic of being "steeper", and we know that the
slope of the line on a distance/time graph is "speed".

3 0

3 years ago

Stars combine Hydrogen to make Helium during nuclear fusion. Living things are made of heavier elements like Carbon, Oxygen, Iro

alex41 [277]

They were formed in the nuclear fusion reaction inside older stars.

As a star burns, fusion reactions inside its core create heavier elements. Those materials are released when the star dies of old age in an explosion.

8 0

3 years ago

Use the five rules to determine the validity of this categorical syllogism:

Novay_Z [31]

Question:

The five rules are;

"The middle term must be distributed in at least one premise.

If a major or minor term is distributed in the conclusion, then it must be distributed in the premises.

No syllogism can have two negative premises.

If either premise is negative, the conclusion must be negative.

No syllogism with a particular conclusion can have two universal premises."

Answer:

The categorical syllogism is invalid as it does not meet thr requirements of rule 2

Invalid because it breaks rule #2.

Explanation:

An argument whose conclusion is implied based on the logical stipulation of the premise is a deductive argument

A syllogism is a deductive argument that makes use of deductive reasoning to come to conclusion, considering a number of of two or more premises which are taken to be true.

For categorical syllogism, we have

If A is in C, then B is in C

Based on the five rules, we have

1. The middle term must be distributed at least once

Here, the middle term is all neutron stars are extremely dense hence i says something about all items in a category, therefore it is distributed

2. If a term is distributed in the conclusion, then it must be distributed in the premise.

Here, the distributed term in the conclusion are "extremely dense objects" is not distributed in the premise, therefore the categorical syllogism is invalid.

4 0

3 years ago