can someone proofread my Big freeze theory of the universe? does it make sense?

Answer:

The scientific questions here are:

a) How will climate change affect forests

b) How did life on Earth begin

c) Why did dinosaurs go extinct

Explanation:

Scientific question are logical quantifiable questions, whose answers can be measured. A good scientific question must have answers that can be tested by a carefully designed experiment or measurement. Some qualities like "prettiest" and "amazing" cannot be tested for nor are they measurable, and hence, they do not make a testable component of good scientific question.

Answer:

1.92 kg of nitrogen.

Explanation:

The following data were obtained from the question:

Heat absorbed (Q) = 384000 J

Note: Heat of vaporisation (ΔHv) of nitrogen = 5600 J/mol

Next, we shall determine the number of mole of nitrogen that absorbed 384000 J.

This is illustrated below:

Q = mol·ΔHv

384000 = mole of N2 x 5600

Divide both side by 5600

Mole of N2 = 384000/5600

Mole of N2 = 68.57 moles

Next, we shall convert 68.57 moles of nitrogen, N2 to grams.

This can be obtained as follow:

Molar mass of N2 = 2 x 14 = 28 g/mol.

Mole of N2 = 68.57 moles.

Mass of N2 =..?

Mole = mass /molar mass

68.57 = mass of N2 /28

Cross multiply

Mass of N2 = 68.57 x 28

Mass of N2 = 1919.96 g

Finally, we shall convert 1919.96 g to kilograms.

This can be achieved as shown below:

1000g = 1 kg

Therefore,

1919.96 g = 1919.96/1000 = 1.92 kg.

Therefore, 1.92 kg of nitrogen were burned off.

Answer:

Explanation:

i cheat on Acellus cause I dont care about school. If i did I would be going to public school... Im never gonna use this info in my life so I dont bother learning it.

Answer:

425 m

Explanation:

From the question,

v = 2x/t.................... Equation 1

Where v = speed of sound in air, x = Length of the lake, t = time.

make x the subject of the equation

x = vt/2............... Equation 2

Given: t = 2.5 s

Constant: v = 340 m/s.

Substitute these values into equation 2

x = 340(2.5)/2

x = 425 m.

Hence the length of the lake is 425 m

Answer:

73.8 km/h

Explanation:

The velocity of object A relative to object B is:

v = va − vb

Let's say east is +x and north is +y, and angles are measured from +x.

The velocity of the first car in the x direction is:

18 km/h cos 135° = -9√2 km/h

The velocity of the first car in the y direction is:

18 km/h sin 135° = 9√2 km/h

The velocity of the second car in the x direction is:

60 km/h cos 270° = 0 km/h

The velocity of the second car in the y direction is:

60 km/h sin 270° = -60 km/h

The relative velocity in the x direction is:

vₓ = -9√2 km/h − 0 km/h = -9√2 km/h ≈ -12.7 km/h

The relative velocity in the y direction is:

vᵧ = 9√2 km/h − (-60 km/h) = 9√2+60 km/h ≈ 72.7 km/h

The speed, or magnitude of the velocity, is:

v = √(vₓ² + vᵧ²)

v = √((-12.7 km/h)² + (72.7 km/h)²)

v ≈ 73.8 km/h

Answer:

1666.7 ETB (birr)

833.3 ETB (birr)

2083.3 ETB (birr)

Explanation:

The first worker

5000*1/3=1666.7

The second worker

5000*1/6=833.3

The third worker

5000*5/12=2083.3

Hope this helps :) ❤❤❤

Answer:

B. The dentist uses X-ray radiography, which takes too short a time to cause those problems.

Explanation:

The statement B would best inform Sally of the level of risk. The dentist uses X-ray radiography, which takes too short a time to cause those problems and risk.

X-ray imaging provides images of human internal organs. The photos depict your body parts in various colors of black and white.

Because various tissues absorb varying quantities of radiation, this is the case. Because calcium absorbs the most x-rays, bones appear white.

When X-ray radiation passes into our bodies, it damages molecular structures and may cause injury.

Human cells are damaged by extremely high doses of radiation, as indicated by skin burns, hair loss, and an increased risk of cancer.

Sally is concerned about the X-ray images her dentist plans to take of her teeth. She has read that X-rays can cause tissue effects, such as skin reddening and hair loss.

The statement B would best inform Sally about the level of risk. The dentist uses X-ray radiography, which takes too short a time to cause those problems and risk.

Hence, statement B would best inform Sally about the level of risk.

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Answer: It has fewer decibels.

Explanation:

In a sound-wave, the intensity is defined as the power carried by the wave. The decibel is a measure of the ratio between two quantities. And in acoustics is used as the unit of the sound pressure level, which is related to the intensity of the wave, then:

As the intensity increases, we also should notice an increase in the decibels.

How is a less-intense wave different from a more-intense wave?

The less-intense wave has fewer decibels.

Answer:

It has fewer decibels.

Explanation:

Answer:

D. Electron - group geometry

Explanation:

Just did it boom THE BANK BUSTA WINS AGAIN

Answer:

A farmer with a field of solar panels.

Explanation:

The closest to a locally sources energy would have been

A coal mine located in their county.

But coal as an energy source is not environmentally friendly due to carbon emission, and should not be what the group should advocate for.

The best bet for them is

A farmer with a field of solar panels.

As solar panels are a source of green energy and green energy is what the environmental group should often and always advocate for

Answer:

Forces come in pairs, so the force of gravity (9.8 N) with the mans weight (794N) on the earth is counteracted with the normal force ( the force of the earth back on the man) which is the same

Explanation:

Forces are available in pairs, so the force of gravity (nine.8 N) with the man's weight (794N) on the planet is counteracted with the everyday force ( the pressure of the earth again on the man) that's identical.

Gravitational force is a pressure that draws any items with mass. We name the gravitational force appealing as it constantly attempts to tug loads collectively, it never pushes them apart. In reality, every item, together with you, is pulling on each other objects inside the complete universe.

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Answer:

560 N/m

Explanation:

F = kx

75 N = k (0.61 m − L)

210 N = k (0.85 m − L)

Divide the equations:

2.8 = (0.85 − L) / (0.61 − L)

2.8 (0.61 − L) = 0.85 − L

1.708 − 2.8L = 0.85 − L

0.858 = 1.8L

L = 0.477

Plug into either equation and find k.

75 = k (0.61 − 0.477)

k = 562.5

Rounded to two significant figures, k = 560 N/m.

Answer:

The concentration of OH⁻ in the mixture is 0.05 M

Explanation:

The reaction of neutralization between HCl and NaOH is the following:

H⁺(aq) + OH⁻(aq) ⇄  H₂O(l)

The number of moles of HCl is:

[tex] n_{HCl} = C*V = 0.1 mol/L*0.250L = 0.025 moles [/tex]

Similarly, the number of moles of NaOH is:

[tex] n_{NaOH} = C*V = 0.2 mol/L*0.250L = 0.05 moles [/tex]

Now, from the reaction of HCl and NaOH we have the following number of moles of NaOH remaining:

[tex] n_{NaOH} = 0.05 moles - 0.025 moles = 0.025 moles [/tex]

Finally, the concentration of OH⁻ in the mixture is:

[tex]C =\frac{n_{NaOH}}{V_{T}}=\frac{0.025 moles}{0.250*2 L} = 0.05 moles/L[/tex]

Therefore, the concentration of OH⁻ in the mixture is 0.05 M.

I hope it helps you!

Answer:

The answer is B.

Explanation:

Given that the current (Ampere) in a series circuit is same so we can ignore it. We can assume that the total voltage is 60V and all the 3 resistance are different, 20Ω, 40Ω and 60Ω. So first, we have to find the total resistance by adding :

Total resistance = 20Ω + 40Ω + 60Ω

= 120Ω

Next, we have to find out that 1Ω is equal to how many voltage by dividing :

120Ω = 60V

1Ω = 60V ÷ 120

1Ω = 0.5V

Lastly, we have to calculate the voltage at R1 so we have to multiply by 20 (R1) :

1Ω = 0.5V

20Ω = 0.5V × 20

20Ω = 10V

Answer:

165.73 K

Explanation:

The computation of HooRU's temperature is shown below:-

As per the stefan's law, the power radiated by black body radiations which is

[tex]P = eA\sigma T^4[/tex]

where  

A indicates surface area

e indicates emissitivity

T indicates temperature

now, we will put the values in the above equation

[tex]13.5 = 0.209 \times 1.51 \times \sigma \times T^4[/tex]

After solving the above equation we will get temperature which results

= 165.73 K

Therefore for computing the HooRU's temperature we simply applied the above formula.

Answer:

4) three

Explanation:

Assuming you mean 1.365248×10⁷, 2% of that is:

0.02 (1.365248×10⁷) = 0.027305×10⁷

So the number is:

1.365248×10⁷ ± 0.027305×10⁷

We need to round this number so that there is uncertainty only in the last digit.

1.37×10⁷ ± 0.03×10⁷

There are three significant figures in 1.37.

Answer:

Length contraction

A moving object traveling at a velocity approaching the speed of light will appear to be shorter or to have undergone contraction.

The proportion by which the object is observed to have contracted is given by Lorentz transformation as follows;

[tex]L = L_{0}\cdot \sqrt{1 -\dfrac{v^{2}}{c^{2}}}= \dfrac{L_{0}}{\gamma }[/tex]

Time dilation

As the relative speed of motion of an object approaches the speed of light, the clock in the frame in motion will be observed to be moving slowly or dilated in a proportion given by Lorentz transformation as follows;

[tex]T = \dfrac{T_{0}}{\sqrt{1 -\dfrac{v^{2}}{c^{2}}}}[/tex]

Explanation:

Example of length contraction example

Two square boxes of side length L which are travelling at a velocity of 0.9 × c, are going to arranged in a single box of side side length  L according to length contraction Lorentz transformation, to  stationary observer we have

[tex]2 \times L\cdot \sqrt{1 -\dfrac{(0.9 \cdot c)^{2}}{c^{2}}}= 0.8 \cdot L[/tex]

To the stationary observer, the 2 boxes of length L will fit side by side in the single box of length L, while to those on the space ship carrying the boxes, the size of the single box is  [tex]L\cdot \sqrt{1 -\dfrac{(0.9 \cdot c)^{2}}{c^{2}}}= 0.4 \cdot L[/tex], which will not contain half of one box

Example of of time dilation example

Twin A of two twins, twin A and B went on a space journey at the speed of 0.87·c for 5 years, the number of years past for twin B when they meet again will be [tex]T = \dfrac{5}{\sqrt{1 -\dfrac{(0.87\cdot c)^{2}}{c^{2}}}} = 10.14 \ years[/tex]

Answer:

Explanation:

We shall apply work energy theorem to calculate the initial velocity just after the collision .

Their kinetic energy will be equal to work done by friction .

force of friction = μ mg , where μ is coefficient of friction , m is total mass and g is acceleration due to gravity

force = .463 x 3210 x 9.8

= 14565.05 N

work done = force x displacement

= 14565.05 x 14.54 = 211775.88 J

now applying work energy theorem

1/2 m v² = 211775.88 , m is composite mass , v is velocity just after the collision

.5 x 3210 x v² = 211775.88

v² = 131.94

v  11.48 m /s

Answer:

t=7.25 sec

Explanation:

840=16t'2,

Answer:

4,524,660 N

Explanation:

Assuming the submarine's density is uniform, 1/9th of the submarine's mass is equal to the mass of the displaced water.

m/9 = (1026 kg/m³) (50 m³)

m = 461,700 kg

mg = 4,524,660 N

Answer:

Ub = 221.99m/s

Explanation:

(Ma x Ua)+(Mb x Ub) = (Ma + Mb)V

(331 x 3.87)+(208 x Ub) = (331 + 208)88

(1257.8) + (208 x Ub) = 47432

(208 x Ub) = 47432 - 1257.8

(208 x Ub) = 46174.2

Ub = 46174.2/208 = 221.99m/s

Ub = 221.99m/s

Answer:

4.75

Explanation:

M1V1 + M2V2 = M1V3 + M2V4

[(331*3.87) , 90°] + 0 = [(331*0.888) , 90°] + M2V4

M2V4 = 987.042 , 90°

divide through by M2

V4 = 4.75 m/s east

Answer:

The object would weight 63 N on the Earth surface

Explanation:

We can use the general expression for the gravitational force between two objects to solve this problem, considering that in both cases, the mass of the Earth is the same. Notice as well that we know the gravitational force (weight) of the object at 3200 km from the Earth surface, which is (3200 + 6400 = 9600 km) from the center of the Earth:

[tex]F_G=G\,\frac{M_E\,m}{d^2} \\28\,\,N=G\,\frac{M_E\,m}{9600000^2}[/tex]

Now, if the body is on the surface of the Earth, its weight (w) would be:

[tex]F_G=G\,\frac{M_E\,m}{d^2} \\w=G\,\frac{M_E\,m}{6400000^2}[/tex]

Now we can divide term by term the two equations above, to cancel out common factors and end up with a simple proportion:

[tex]\frac{w}{28} =\frac{9600000^2}{6400000^2} \\\frac{w}{28} =\frac{9}{4} \\\\ \\w=\frac{9\,*\,28}{4}\,\,\,N\\w=63\,\,N \\[/tex]

Answer:

2.38 m/s

Explanation:

Momentum is conserved:

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

After the collision, they move at the same speed, so v₁ = v₂ = v.

m₁u₁ + m₂u₂ = (m₁ + m₂) v

Plugging in numbers:

(115 kg) u₁ + (133 kg) (-1.59 m/s) = (115 kg + 133 kg) (0.250 m/s)

u₁ = 2.38 m/s

Answer:

3000 N

Explanation:

as we know that

pressure=force/area

so force=thurst

pressure=thurst/area

thyrst=pressure*area

pressure=150 Nm^-2

area=20m^2

so thurst=150*20=3000 N or 3*10^3 N

Answer:

The field would reverse its poles.

Explanation:

The current flow will reverse directions which will reverse the poles in the magnetic field created around the iron nail.

If she connects the battery in the opposite direction, the magnetic field would reverse its poles.

The magnetic field is the region of space where an object experiences the magnetic force and obtain magnetic properties.

A wire is connected to the positive end of the battery and curls around an iron nail and connects back with the negative side of the battery. This arrangement will let the current flow from the positive end of the battery towards the negative terminal of the battery.

If the battery is connected in the opposite direction, the current will flow from negative to positive terminal.

Therefore, If she connects the battery in the opposite direction, the magnetic field would reverse its poles.

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Answer:

A.) Find the attached file

B.) 1.536 J

C.) 123N

Explanation:

Given that the force (F) in Newtons, of his breath as a function of the distance along the straw (x) in meters, can be modeled as a linearly decreasing function for the first half of the straw,

Half of the straw = 12.5 cm

Let Force F = dependent variable

And distance x = independent variable

A.) Find the attached file for the graph.

Sinnce the force decreases by half along the first half of the straw. Assume there is negligible friction and the straw is held horizontally

B.) Given that the mass M = 12g = 12/1000 = 0.012kg

And Velocity V = 16m/s

The workdone = the kinetic energy of the split ball

WD = 1/2mv^2

Substitutes m and V into the formula

WD = 1/2 × 0.012 × 16^2

WD = 1.536 Joule

C.) The maximum force acts on the spit ball will be at maximum kinetic energy.

Since work done = force × distance

Where distance = 12.5 cm

F × S = 1/2mv^2

Substitutes all the parameters

F × 0.0125 = 1.536

Make F the subject of formula

F = 1.536/0.0125

F = 122.88 N

The maximum force F0, that acts on the spitball is therefore equal to 123 N approximately.

We have that for the Question "(a) Sketch a plot of the force of his breath as a function of position along the straw, labeling the force at x = 0 as F0.

(b) If the spitball begins from rest and leaves the straw with a speed of 16 m/s, how much work is done on the spitball?

(c) What is the maximum force F0, that acts on the spitball?"

It can be said that

From the question we are told

mass of spitball = 12g through a 25.0 cm straw

Generally the equation for workdone is mathematically given as

[tex]= \frac{1}{2}mv^2 - 0\\\\= \frac{1}{2} * 12*10^{-3} * 16^2\\\\= 1.536J[/tex]

Maximum force

[tex]w = \frac{1}{2}*\frac{x_0}{2}*\frac{F_0}{2} + x_0*\frac{F_0}{2}\\\\w = \frac{5}{8}x_0F_0[/tex]

Therefore,

[tex]F_0 = \frac{8w}{5x_0}\\\\F_0 = \frac{8*1.536}{5*25*10^[-2]}\\\\F_0 = 6.4N[/tex]

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Answer:

Answer B)  An increase in [tex]\mu_S[/tex]

Explanation:

Since we are talking about the force of static friction, due to its definition as the product between the normal force to the surface times the coefficient of static friction, the only two ways such force could increase is due to an increase in the normal force, or an increase in the coefficient of static friction [tex]\mu_S[/tex].

So the only valid answer is answer B)

Explanation:

It is given that,

The angle of projection is 60 degrees

Initial velocity of the ball is 120 m/s

We need to find the time taken to get to the maximum height and the time of flight.

Time taken to reach the maximum height is given by :

[tex]T=\dfrac{u^2\sin^2\theta}{2g}[/tex]

g is acceleration due to gravity

[tex]T=\dfrac{(120)^2\times \sin^2(60)}{2\times 10}\\\\T=540\ s[/tex]

(ii) Time of flight,

[tex]t=\dfrac{2u\sin\theta}{g}[/tex]

So,

[tex]t=\dfrac{2\times 120\times \sin(60)}{10}\\\\t=20.78\ s[/tex]

Hence, this is the required solution.

Answer:

1)  v = 1.19 m / s , 2)     P₁ = 9.308 10⁴ Pa  

Explanation:

In this exercise we will simulate the emission of urine as a fluid mechanics system

1) they indicate the urine flow rate Q = 0.0060 m³ / s, they also give the diameter of the tube 8.0 cm, they ask us the speed.

   Let's use the continuity equation

            Q = v A

The area of ​​a cycling tube is

            A = π r² = π d² / 4

we substitute

            Q = v π d² / 4

            v = 4Q / π d²

let's calculate

            v = 4 0.006 / (π 0.08²)

            v = 1.19 m / s

2) they ask to find the pressure in the bladder, for this we use the Bernoulli equation, where the index is for the bladder and the index 2 is for the exit point

            P₁ + ½ ρ v₁² + ρ g y₁ = P₂ + ½ ρ v₂² + ρ g y₂

in the exercise it indicates that the outlet pressure is equal to the atmospheric pressure P₂ = 1,013 10⁵ Pa, the velocity of the liquid in the bladder is v₁ = 0 and the height difference 1.0 m

           P₁ = P₂ + ½ ρ v₂² + ρ g (y₂-y₁)

let's calculate

          P₁ = 1.013₁ 10⁵⁵ + ½ 1000 1.19 + 1000 9.8 (0-1)

          P₁ = 1.013 105 + 595 - 9800

          P₁ = 9.308 10⁴ Pa

Answer:

(a) 1900 kg m²

(b) 8950 Nm

Explanation:

(a) The moment of inertia of a rod about its end is I = ⅓mL².

For 3 rods of mass m = 135 kg and length L = 3.75 m, the total moment of inertia is:

I = 3 (⅓ (135 kg) (3.75 m)²)

I = 1900 kg m²

(b) Net torque = moment of inertia × angular acceleration

∑τ = Iα

First, find the angular acceleration.

ω₀ = 0 rad/s

ω = 6.0 rev/s (2π rad/rev) = 37.7 rad/s

t = 8.0 s

α = (37.7 rad/s − 0 rad/s) / 8.0 rad/s = 4.71 rad/s²

∑τ = Iα

∑τ = (1900 kg m²) (4.71 rad/s²)

∑τ = 8950 kg m² / s²

∑τ = 8950 Nm

Answer:

we need it to work and without it we dont have strength to do anything

Answer:

energy is important to all living organisms. energy for producers comes from the sun, and energy for consumers comes from other living organisms. the abundance of energy available for organisms impacts the population.