dark energy has been hypothesized to solve which problem?

Answer:

1.84 kJ  (kilojoules)

Explanation:

A specific heat of 0.46 J/g Cº means that it takes 0.46 Joules of energy to raise the temperature of 1 gram of iron by 1 Cº.

If we want to heat 50 g of iron from 20° C to 100° C, we can make the following calculation:

Heat = (specific heat)*(mass)*(temp change)

Heat = (0.46 J/g Cº)*(50g)*(100° C -  20° C)

[Note how the units cancel to yield just Joules]

Heat = 1840 Joules, or 1.84 kJ

[Note that the number is positive:  Energy is added to the system.  If we used cold iron to cool 50g of 100° C water, the temperature change would be (Final - Initial) or (20° C - 100° C).  The number is -1.84 kJ:  the negative means heat was removed from the system (the iron).

Answer:

No.

Explanation:

Hot spots don't appear at the barriers of tectonic plates, instead, they originate at hot centres known as mantle plumes. Mantle plumes exist below the tectonic plates and may develop a string of volcanoes on the Earths surface.

Answer:

D) 4.9 m/s

Explanation:

Speed of Object in Free Fall

s = Rate of Acceleration, Due to Gravity × Length of Time

s = 9.8 × 2.0

s = m/s (Round Up to The Nearest Whole Number)

--

m/s = 9.8 ÷ 2.0 = 4.9 m/s

Answer:

35N

Explanation:

force=mass×gravity

the mass is 5 and the gravity is 7 therefore:

force=7×5

=35N

I hope this helps

Explanation:

because its speed (v) is 0

Answer:

B

Explanation:

I don't know but its b

The fundamental frequency, wavelength of the wave, and mass per unit

length of the string, determines the tension in the string.

Reasons:

From a similar question, we have;

Fundamental frequency, f₁ = 146.8 Hz

Oscillating length on the D-string, λ₁ = 0.61 m

Mass of the string = 1.5 × 10⁻³ kg.

We have;

[tex]\displaystyle f_1 \cdot \lambda _1 =\mathbf{ \sqrt{\frac{T}{m/L} }}[/tex]

Therefore;

[tex]\displaystyle T = \mathbf{\frac{f_1^2 \cdot \lambda _1^2 \cdot m }{L}}[/tex]

Which gives;

[tex]\displaystyle T = \frac{146.8^2 \times 0.61^2 \times 1.5 \times 10^{-3} }{0.61 } \approx \mathbf{19.718}[/tex]

The tension to which the D-string must be tuned, T ≈ 19.718 Newtons

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The parameters given in a similar question obtained online are;

The fundamental frequency of the tone, f₁ = 146.8 Hz

The oscillating length on the D-string, λ₁ = 0.61 m

The mass of the string = 1.5 × 10⁻³ kg.

Answer:

A. Fusion Reactions

Explanation:

1. Since the body is thrown vertically upward, the only force acting on it as it rises and falls is gravity, which causes a constant downward acceleration with magnitude g = 9.8 m/s². Because this acceleration is constant, we can use the formula

v² - u² = 2a ∆x

where

u = initial speed

v = final speed

a = acceleration

∆x = displacement

At its maximum height, some distance y above the point where the body is launched, the body has zero velocity, so

0² - (20 m/s)² = 2 (-9.8 m/s²) y

Solve for y :

y = (20 m/s)² / (2 (9.8 m/s²)) ≈ 20.4 m

2. Relative to the ground, the body's maximum height is 60 m + 20.4 m ≈ 80.4 m.

3. At any time t ≥ 0, the body's vertical velocity is given by

v = 20 m/s - gt

At the highest point, we have

0 = 20 m/s - (9.8 m/s²) t

and solving for t gives

t = (20 m/s) / (9.8 m/s²) ≈ 2.04 s

4. The body's height y above the ground at any time t ≥ 0 is given by

y = 60 m + (20 m/s) t - 1/2 gt²

Solve for t when y = 0 :

0 = 60 m + (20 m/s) t - 1/2 (9.8 m/s²) t²

Using the quadratic formula,

t = (-b + √(b² - 4ac)) / (2a)

(and omitting the negative root, which gives a negative solution) where a = -1/2 (9.8 m/s²), b = 20 m/s, and c = 60 m. You should end up with

t ≈ 6.09 s

5. At the time found in (4), the body's velocity is

v = 20 m/s - g (6.09 s) ≈ -39.7 m/s

Speed is the magnitude of velocity, so the speed in question is 39.7 m/s.

Answer:

hi I don't know sorry sorry forgive me

Explanation:

sorry

Distance (s) =20 m

Initial velocity =0 m/s

g=10 m/s²

By using the formula:

v²= u²+ 2as

v²=0²+ 2×10×15

v²= 300

V= 10root over 3

[tex]10 \sqrt{3} [/tex]

For calculating time,

v= u+ at

10 root over 3 = 0+ 10t

10 root over= 10t

t = 1 root over 3

t = 1.73 s

[tex]1 \sqrt{3} [/tex]

The the stone will hit the ground with a velocity of 10 root over 3 m/s in 1 root over 3 sec.

Answer:

6500N

Explanation:

F = ma so therefore Were given mass (m) = 1500 kg, acceleration (a) = 5 m/s2, well have to calculate the force to be:

1500 x 5 = 6500 N

Answer:

Very simple. The charge Q= 20 C. the formula for Q= I* t. now I= Q/t = 20/1s = 20 Amps.

Explanation:

The current given that the charge is 10C and the time is 4 seconds is gotten as Current = 2.5 Amps

Given Data

Charge = 10 Columbs

Time = 4 seconds

Current = ?

Electrical current is defined by how much electric charge has been transferred per second, giving the following relationship:

Charge = Current*Time

Rearranging this we get:

Current = Charge/Time

The symbol for charge is Q , it is measured in coulombs (C).

The symbol for current is I , it is measured in amperes (A).

The symbol for time is T, it is measured in seconds (s).

Substituting our given Data into the expression we have

Current = 10/4

Current = 2.5 Amps

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Answer:

jogging

Explanation:

Jogging is often defined as running at a pace less than 6 miles per hour (mph), and it has some significant benefits for people who want to improve their health without overdoing it.

A 12 volt car battery will produces more current than a 1.5 volt battery for a TV remote because the car battery has a greater difference in electric potential energy than a 1.5 Volt battery. The correct answer is D

The potential difference between any two point in a circuit is the work done when one coulomb of charge moves from one point to the other. Potential difference is a kind of electrical pressure difference between two point.

The difference in electric potential in a 12 Volt battery is greater than the difference in electric potential in a 1.5 Volt battery.

According to Ohm's law, Voltage supplied is proportional to current produced. That is, V = lR. Where R = resistance.

A 12 volt car battery will produces more current than a 1.5 volt battery for a TV remote because the car battery has a greater difference in electric potential energy than a 1.5 Volt battery.

Therefore, the correct answer is the option D

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Answer:

0 m

Explanation:

Displacement is the shortest distance from one ppont to another. Here, the girl returns to the same spot after running. Hence, displacement is 0 m.

The velocity of the red cart after the collision is 2 m/s

From the law of conservation of momentum, initial momentum of system = final momentum of system.

m₁v₁ + m₂v₂ = m₁v₃ + m₂v₄ where m₁ = mass of red cart = 4 kg, v₁ = velocity of red cart before collision = + 4 m/s, v₃ = velocity of red cart after collision, m₂ = mass of blue cart = 1 kg, v₂ = velocity of blue cart before collision = 0 m/s (since it is initially at rest) and v₄ = velocity of blue cart after collision = + 8 m/s.

Substituting the values of the variables into the equation, we have,

m₁v₁ + m₂v₂ = m₁v₃ + m₂v₄

4 kg × 4 m/s + 1 kg × 0 m/s = 4v₃ + 1 kg × 8 m/s

16 kgm/s + 0 kgm/s =  4v₃ + 8 kgm/s

16 kgm/s =  4v₃ + 8 kgm/s

16 kgm/s - 8 kgm/s =  (4 kg)v₃

(4 kg)v₃ = 8 kgm/s

Divide both sides by 4 kg, we have

v₃ = 8 kgm/s ÷ 4 kg

v₃ = 2 m/s

The velocity of the red cart after the collision is 2 m/s.

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The vectors point along the axis of rotation with a direction determined by an arrow.

There are two types of physical quantity one is a scaler and another one is a vector.

The quantity that requires only megnitude to define is known as the scalar quantity. While the vector quantities need both megnitude and the direction to define.

The vector quantity is represented by an arrow. The vectors point along the axis of rotation with a direction determined by an arrow.

The angular quantities L, omega, and alpha are vector quantities.

Hence arrow is the correct answer for the blank.

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The direction of the vectors of angular momentum and L, angular velocity omega and the mass alpha is determined using the right hand rule.

Righthand rule in physics states that, when we curl our right hand fingers, the direction of the angular momentum and velocity will be in the direction of thumb and curl of fingers determine the axis of rotation.

Angular momentum is a vector quantity defined as the product of moment of inertia and angular velocity where, the angular velocity ω is the rotational analogue of linear velocity i.e.. product of the linear velocity and radius of rotational path.

Therefore, the angular quantities L, angular velocity ω along the axis of rotation can be determined using the right hand rule. Where direction of thump represents the direction of vector components.

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Answer:

4×2×3= 24dm^3

.......................

If both masses double in size and their separation between them triples. 13..33 N will be the force between the masses.

Newton's law of gravity states that each particle having mass in the universe attracts each other particle with a force known as the gravitational force.

Gravitational force is proportional to the product of the masses of the two bodies and inversely proportional to the square of their distance.

Given data:

The gravitational force = 30 N

Mass 1 =m₁

Mass 2=m₂

Distance between charges = R

Condition given:

Mass 1 = 2m₁

Mass 2= 2m₂

Distance  between charges = 3R

[tex]\rm F = \frac{Gm_1m_2}{R^2}[/tex]

Case 2;

[tex]\rm F'=\frac{G(2m_1)(2m_2)}{(3R)^2} \\\\ F'=\frac{4}{9} \frac{Gm_1m_2}{R^2} \\\\ F'=\frac{4}{9} F \\\\ F'=\frac{4}{9} \times 30 \\\\ F'=13.33 \ N[/tex]

Hence, the forces between the masses will be 13..33 N.

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Answer:

To get the latitude of the address in cell B2, use the formula = GetLatitude (B2) To get the longitude of the address in cell B2, use the formula = GetLongitude (B2) To get both the latitude and longitude of the address in cell B2, use the formula = GetCoordinates (B2)

Explanation:

CAN I GET BRAINLIEST

Explanation:

Magnetic fields are areas where an object exhibits a magnetic influence. The fields affect neighboring objects along things called magnetic field lines. A magnetic object can attract or push away another magnetic object. You also need to remember that magnetic forces are NOT related to gravity.

The natural light display called aurora borealis is located in the northern

hemisphere.

There are two types of aurora which are called aurora borealis and aurora

australis. The aurora borealis is located in the Northern hemisphere while

the aurora australis is located in the Southern hemisphere.

They receive their energy through the interaction of charged particles

on the Sun and Earth to produce the light display. An example

of the interaction involves solar wind with atoms of the upper atmosphere.

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Answer:

northern and southern hemisphere

Explanation:

Answer:

55.84 look at periodic table

so 55.84*3= 167.52gFe

Answer:

When waves are closer together and there are more waves, then the wave has a higher frequency.

Explanation:

Hoped this helped.

Answer:

frequency

Explanation:

Answer:

Period: 1/3= 0.33 seconds.

The frequency and period of the metronome's vibration when the metronome is set at 180 is 3Hz and 0.33 s.

Frequency is the number of oscillations per second.

The time period is the reciprocal of the frequency.

Given is the metronome set at 180.

The reading of metronome = frequency in seconds = 180 / 60 = 3 Hz

The time period of the metronome's vibration T = 1/3 = 0.33 seconds.

Thus, the frequency and the time period is 3Hz and 0.33 s.

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Answer:

6J

Explanation:

simply apply kinetic energy definitoon:

[tex]k = \frac{1}{2} mv {}^{2} = \frac{1}{2} 3 \times 2 {}^{2} = 6[/tex]

Answer:

3.125 Kilometers

Explanation:

To answer this you just multiply 12.5 by .25 (since 15 minutes is a quarter of an hour) to get 3.125 kilometers ridden.

Answer:

7.84 s

Explanation:

Ok, one step at a time. We know the mass of the projectile, we know the force. Acceleration is easily obtained from Newton second law:

[tex]\vec F = m\vec a[/tex][tex]2.5\times 10^5 = 5.6a \rightarrow a = (2.5/5.6) \times 10^5 = 4.46 \times 10^4 ms^-^2[/tex].

At this point, we know the acceleration, we know initial and final velocity, we can time the ammount of time it took to get there.

[tex]v= v_0 +at \rightarrow 3.5\times10^3 = 0 + 4.46\times10^4 t\\t= \frac{3.5\times10^3}{4.46\times10^4} = 7.84 s[/tex]