The partial negative charge in a molecule of water occurs because

the video discusses four potential models of how the expansion of the universe changes with time. drag the correct model descrip

lapo4ka [179]

Only the coasting model makes the assumption that the universe's expansion pace never changes.

The current expansion of the cosmos is predicted by all four hypotheses.

Only the recollapsing model foresees the eventual contraction of the universe.

The average mass density of the cosmos is predicted to be exactly the critical density only under the critical model.

The cosmos is only predicted to be expanding more quickly than it did in the distant past by the accelerating model.

Cosmologists use observations of radiation released soon after the Big Bang to determine the expansion rate, often known as the Hubble constant.

Since the unexpected finding that the universe's expansion is speeding up in 1998, cosmologists have incorporated repulsive dark energy into their theory of cosmic development. The Hubble constant's inconsistent values might be resolved by early dark energy, an additional amount of dark energy present in the early cosmos. This early dark energy would have accelerated the universe's expansion by exerting external pressure.

To learn more about Universe expansion please visit-
brainly.com/question/16048709
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8 0

2 years ago

*brainlest* An object accelerates from rest with a constant acceleration of 2m/s^2. How far will it have moved after 9s? Equatio

boyakko [2]

Answer: You throw an object upwards from the ground with a velocity of 20m/s and it is subject to a downward

acceleration of 9.8 m/s2. How high does it go?

Given Formula Set up Solution

vi=20 m/s

vf=0 m/s

a=-9.8 m/s2

x=?

vf

2 = vi

2 + 2a x (0 m/s)2= (20 m/s)2 + 2 (-

9.8 m/s2) x

x=20.4 meters

Explanation: i known/ i hoped that helped.

6 0

3 years ago

Circuit A in a house has a voltage of 208 V and is limited by a 40.0-A circuit breaker. Circuit B is at 120.0 V and has a 20.0-A

Setler79 [48]

Given Information:

Voltage of circuit A = Va = 208 Volts

Current of circuit A = Ia = 40 Amps

Voltage of circuit B = Vb = 120 Volts

Current of circuit B = Ib = 20 Amps

Required Information:

Ratio of power = Pa/Pb = ?

Answer:

Ratio of power = Pa/Pb = 52/15

Explanation:

Power can be calculated using Ohm's law

P = VI

Where V is the voltage and I is the current flowing in the circuit.

The power delivered by circuit A is

Pa = Va*Ia

Pa = 208*40

Pa = 8320 Watts

The power delivered by circuit B is

Pb = Vb*Ib

Pb = 120*20

Pb = 2400 Watts

Therefore, the ratio of the maximum power delivered by circuit A to that delivered by circuit B is

Pa/Pb = 8320/2400

Pa/Pb = 52/15

4 0

3 years ago

Martin is conducting an experiment. His first test gives him a yield of 5.2 grams. His second test gives him a yield of 1.3 gram

Bogdan [553]

Complete Question

Martin is conducting an experiment. His first test gives him a yield of 5.2 grams. His second test gives him a yield of 1.3 grams. His third test gives him a yield of 8.5 grams. On average, his yield is 5.0 grams, which is close to the known yield of 5.1 grams of substance. Which of the following are true?

A His results are accurate but not precise.

B His results are neither accurate nor precise.

C His results are both accurate and precise

D His results are precise but not accurate.

Answer:

Correct option is A

Explanation:

From the question we are told that

The yield of the first test $k = 5.2 \ g$

The yield of the second is $u = 1.3 \ g$

The third yield is $p = 8.5 \ g$

The average yield $A = 5.0 \ g$

The know yield is $A_S = 5.1 \ g$

From the data given we see that

$A_S \ne A$

Since his average yield is closer to the known yield then the answer is accurate

But since the yield for each test are not repeated the answer is not precise

So the answer is accurate but not precise

4 0

3 years ago

An aluminum wire with a diameter of 0.100mm has a uniform electric field of 0.200V/m imposed along its entire length. The temper

Aleonysh [2.5K]

The linear resistivity of this wire is equal to 3.15 × 10⁻⁸ Ωm.
The current density in this wire is equal to 6.35 × 10⁶ A/m².
The total current in a wire is equal to 0.0499 Amp.
The drift speed of the conduction electrons is equal to 6.59 × 10⁻⁴ m/s.
The potential difference between the ends of this wire is equal to 0.4 Volt.

<u>Given the following data:</u>

Diameter of aluminum wire = 0.100 mm.

Uniform electric field of aluminum wire = 0.200 V/m.

Temperature of aluminum wire = 50.0°C.

<u>Scientific data:</u>

Resistivity of aluminum, ρ = 2.82 × 10⁻⁸ Ωm

Temperature coefficient for aluminum, α = 3.9 × 10⁻³ °C⁻¹.

<h3>How to determine the resistivity?</h3>

Mathematically, the linear resistivity of a material can be calculated by using this formula:

ρ = ρ₀(1 + αΔT)

ρ = ρ₀(1 + α(T₂ - T₁)

ρ = 2.82 × 10⁻⁸ × [1 + 3.9 × 10⁻³(50 - 20)

Resistivity, ρ = 3.15 × 10⁻⁸ Ωm.

<h3>What is the current density in this wire?</h3>

Mathematically, the current density in a wire can be calculated by using this formula:

J = σE = E/ρ

J = 0.2/3.15 × 10⁻⁸

Current density, J = 6.35 × 10⁶ A/m².

<h3>What is the total current in this wire?</h3>

Mathematically, the total current in a wire can be calculated by using this formula:

I = JA = J(πr²)

I = 6.35 × 10⁶ × (3.142 × 0.00005²)

Total current, I = 0.0499 Amp.

<h3>What is the drift speed of the conduction electrons?</h3>

Mathematically, the drift speed of the conduction electrons can be calculated by using this formula:

V = I/nqA

V = (0.0499 × 0.027)/(6.023 × 10²³ × 27000 × 1.602 × 10⁻¹⁹ × (3.142 × 0.00005²)

Drift speed, V = 6.59 × 10⁻⁴ m/s.

For the the potential difference, we have:

Mathematically, the potential difference between the ends of a wire can be calculated by using this formula:

ΔV = El

ΔV = 0.2 × 2

ΔV = 0.4 Volt.

Read more on drift speed here: brainly.com/question/15219891

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Complete Question:

An aluminum wire with a diameter of 0.100 mm has a uniform electric field of 0.200 V/m imposed along its entire length. The temperature of the wire is 50.0°C. Assume one free electron per atom.

(a) Determine the resistivity.

(b) What is the current density in the wire?

(c) What is the total current in the wire?

(d) What is the drift speed of the conduction electrons?

(e) What potential difference must exist between the ends of a 2.00-m length of the wire to produce the stated electric field?

7 0

2 years ago