Hãy giải thích các khái niệm sau và lấy ví dụ cụ thể để minh họa:
Áp suất chân không tuyệt đối, áp suất tuyệt đối, áp suất khí trời, áp suất dư và áp suất chân
không?

Answer:

Individual organisms live together in an ecosystem and depend on one another. ... Some organisms can make their own food, and other organisms have to get their food by eating other organisms. An organism that must obtain their nutrients by eating (consuming) other organisms is called a consumer, or a heterotroph.

The angle of incidence for a complete polarization of incident ray on water is 53.1⁰.

The given parameters;

The angle of incidence for a complete polarization of incident ray on water is calculated by applying Brewster's law as shown below;

[tex]\mu = tan \ \theta[/tex]

where;

The polarizing angle is calculated as;

[tex]\theta = tan^{-1}(1.333)\\\\\theta = 53.1^ 0[/tex]

Thus, the angle of incidence for a complete polarization of incident ray on water is 53.1⁰.

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Answer:

Equal to

Explanation:

with a totally inelastic collision masses combine and velocity is the same.

p initial =p final

p=mv

10kg(20m/s)=20kg(v)

200kg m/s=20kg(v)

v=10m/s

The resulting velocity obtained is less than 10m/s.

We have the following information;

Mass of the first puck = 10 kg

velocity of the first puck = 20 m/s

Mass of the second puck = 20 kg

common velocity = ?

From the law of conservation of linear momentum;

[(10 kg  × 20 m/s) + (20 kg × 0 m/s)] = (10 kg + 20 kg) v

200 + 0 = 30v

v = 200/30

v = 6.67 m/s

Hence, the resulting velocity obtained is less than 10m/s.

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The center mass of the car from the front for the given passengers is 3.46 m.

The given parameters;

Assuming the mass of the passengers is the same, let their mass = m

Keeping the front seat as the reference point, the center mass is calculated as;

[tex]X_{cm} = \frac{ \ 2M(2.8m) \ + \ 3M(3.9m) }{2M + 3M} \\\\X_{cm} = \frac{17.3 Mm}{5M} \\\\X_{cm} = 3.46\ m[/tex]

Thus, the center mass of the car from the front for the given passengers is 3.46 m.

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Answer:

Explanation:

Givens

d = 8.5 meters

vi = 0

a = 9.81

t = ?

Formula

d = vi * t + 1/2 a t^2

Solution

8.5 = 0 + 1/2 9.81 * t^2       multiply both sides by 2

8.5 = 4.095 t^2                  Divide both sides by 4.095

8.5/4.095 = t^2

1.7329 = t^2                       Take the square root of both sides

t = 1.316

It takes 1.316 seconds to hit the ground.

The volume of gasoline you will have on a very hot afternoon when the temperature has raised to 39 °C is 50.009 L

The following data were obtained from the question:

V₂ = V₁[1 + γ(T₂ – T₁)]

= 50 × [1 + 9.50×10⁻⁶(39 – 20)]

=  50 × [1 + 9.50×10⁻⁶(19)]

=  50 × 1.0001805

= 50.009 L

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Answer:

[tex]\boxed {\boxed {\sf 253 \ meters}}[/tex]

Explanation:

We are asked to find the distance a train travels.

We are given the acceleration, initial velocity, and time. Therefore, we will use the following kinematic equation:

[tex]d=v_it+\frac{1}{2}at^2[/tex]

The train starts at a full stop or a velocity of 0 meters per second. It accelerates at a rate of 0.250 meters per second squared for 45.0 seconds.

Substitute the values into the formula.

[tex]d= (0 \ m/s)(45.0 \ s) + \frac{1}{2} (0.250 \ m/s^2)(45.0 \ s)^2[/tex]

Multiply the first two numbers. The units of seconds cancel.

[tex]d= 0 \ m + \frac{1}{2} (0.250 \ m/s^2)(45.0 \ s)^2[/tex]

Solve the exponent.

[tex]d= 0 \ m +\frac{1}{2} (0.250 \ m/s^2)(2025 \ s^2)[/tex]

Multiply the numbers in parentheses. The units of seconds squared cancel.

[tex]d= 0 \ m +\frac{1}{2} (0.250 \ m/s^2 * 2025 \ s^2)[/tex]

[tex]d= 0 \ m +\frac{1}{2} (0.250 \ m * 2025 )[/tex]

[tex]d= 0 \ m + \frac{1}{2} (506.25 \ m)[/tex]

Multiply by 1/2 or divide by 2.

[tex]d=0 \ m + 253.125 \ m \\d= 253.125 \ m[/tex]

The original measurements of acceleration and time both have 3 significant figures, so our answer must have the same. For the number we found, that is the ones place. The 1 in the tenths place tells us to leave the 3.

[tex]d \approx 253 \ m[/tex]

The train travel approximately 253 meters.

The angle the rope make with the vertical when the ball's kinetic energy is halved is 14.78°.

Let K = 1/2mv² be the balls initial kinetic energy when it is pushes horizontally. It rises to a height, h has potential energy U = mgh and has kinetic energy half of its initial kinetic energy. So, K' = 1/2K.

So, from the law of conservation of energy,

K = U + K'

K = U + 1/2K

K - 1/2K = U

K/2 = U

1/2(1/2mv²) = mgh

1/4mv² = mgh

1/4v² = gh

h = v²/4g

Since v = initial speed of ball = 1.3 m/s and g = acceleration due to gravity = 9.8 m/s².

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

h = v²/4g

h = (1.3 m/s)²/(4 × 9.8 m/s²)

h = 1.69 m²/s² ÷ 39.2 m/s²

h = 0.043 m.

Since the length of the rope l = 1.3 m and the distance of the ball from the pivot when it is h metres above its lowest point is L = l - h = 1.3 m - 0.043 m = 1.257 m.

So, the angle the rope makes with the vertical is Ф and cosФ = L/l

= 1.257/1.3

= 0.9669

Ф = cos⁻¹(0.9669)

Ф = 14.78°

So, the angle the rope make with the vertical when the ball's kinetic energy is halved is 14.78°.

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Explanation:

We know that [tex]f = \mu N,[/tex] where N is the normal force and [tex]\mu[/tex] is the coefficient of friction. In this case, Mr. Jones's weight is the normal force therefore, the frictional force on Mr. Jones is

[tex]f = (0.120)(850\:\text{N}) = 102\:\text{N}[/tex]

Explanation:

Q1. Circulatory/respiratory systems: get blood with oxygen and food to leg muscles

Skeletal/muscular systems: make legs move

Nervous system: sense danger, coordinate leg movements

Hormones to change body activity's are sent out by the ___________

Endocrinesystem

Q2. Excess carbon dioxide and oxygen are excreted from the plant through the stomata in the leaves.

Q3. Reproduction is the process by which new living things are created. People, animals, plants, and even bacteria, reproduce. There are two methods by which living things reproduce--asexual or sexual. Asexual reproduction allows for a living thing to reproduce without another member of its species, while sexual reproduction requires genetic material from two different members of the species, usually but not always, a male and a female. There are a few rare species that have the ability to reproduce both sexually and asexually.

Sexual Reproduction

In sexual reproduction, species can be either anisogamous or isogamous. In anisogamous reproduction, there are two parents, generally male and female. In order to reproduce, both contribute a gamete, or reproductive cell containing a haploid, or single set of chromosomes, that will make up the offspring. Each gamete provides half of the offspring’s genetic material. Many animals, including humans, reproduce in this way. Males produce sperm, which fertilize a female’s ova, or egg, within her body during the process of sexual intercourse. The point at which the egg is fertilized is called conception. The union of the two gametes results in a new cell, called a zygote. This cell continuously divides, implanting itself into the female uterus, and developing into what becomes known first as an embryo, and later, as a fetus. It is nourished and grows in the uterus throughout what is referred to as a period of gestation. This length of time varies for different animals. When development is complete, the birth process allows the female parent to deliver the baby that has grown within her, so that it can begin to thrive and grow on its own. Humans can also fertilize eggs externally, through a process called in vitro fertilization. Some animals, particularly those that live in the water, fertilize eggs externally, by releasing sperm and egg into the water, where they join together and become fertilized. Birds and reptiles have their eggs fertilized internally, and then lay eggs, in which the new creature develops, and then is hatched. Flowering plants even reproduce sexually, through a process called pollination. However, depending on the plant, it may self-pollinate, or cross-pollinate.

Asexual Reproduction

In asexual reproduction, a living thing can reproduce without receiving any cells from another living thing. All chromosomes come from one parent causing the offspring to be similar or identical in genetic structure. Organisms that produce asexually include but are not limited to bacteria, molds, yeast and some plants. Methods of asexual reproduction include budding, in which a new organism is formed directly from a part of an organism, such as with plants. Fragmentation means a living thing is split into fragments, which grow to be clones of the original living thing. Molds and starfish are examples of organisms that reproduce through fragmentation. Binary fission occurs when a cell divides into two parts. These organisms may not be genetically identical. Bacteria reproduce in this way. Spore formation is another form of asexual reproduction. According tothe New World Encyclopedia, a spore is a reproductive structure that is adapted for dispersion and survival for extended periods of time in unfavorable conditions. Once conditions are favorable, the spore can develop into a new haploid organism using mitotic division

Q4. We cannot prevent natural earthquakes from occurring but we can significantly mitigate their effects by identifying hazards, building safer structures, and providing education on earthquake safety. By preparing for natural earthquakes we can also reduce the risk from human induced earthquakes.

hope it is helpful

Answer:

.

I did not mean to do this!

can I delete it?

Explanation:

The energies that the ball possess when it is in rest at the top of the hill is electrostatic  potential energy. When the ball at the level ground, it has gravitational potential energy and when it at the half way down hill , it possess rotational kinetic energy.

Potential energy of a body is generated by virtue of its position. When the object is placed at rest on the surface the gravitational field, the stored energy is called gravitational potential energy.

When the object starts to move it gains kinetic energy.  When the ball is at rest on the top of the hill it has the electrostatic potential energy. When starts to roll to the ground , then its potential energy converts to rotational kinetic energy.

When, the ball reaches the ground its kinetic energy again transforms to potential energy where the ball is falling down to the gravitational field and thus it possess gravitational potential energy.

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Answer: C

Explanation:

The answer is choice C.

The sum of the vectors is the resultant vector, which is where the net force is directed.

An example would be if you had a ball rolling on a table and you bumped the ball perpendicular to its initial velocity, then the ball would move at a diagonal angle rather than move straight in the direction where you bumped it.

Acceleration is the change in velocity over time, so the acceleration vector tells us how the velocity's direction is changing.

Answer:

Explanation:

1.) If multiple forces are acting on an object, which statement is always true?

Answer: The acceleration will be directed in the direction of the net force.

2.) If a ball is accelerating down through the air with no horizontal motion, what must be true about the net forces acting on the ball?

Answer: The gravitational force is greater than the drag.

3.) A boy who exerts a 300-N force on the ice of a skating rink is pulled by his friend with a force of 75 N, causing the boy to accelerate across the ice. If drag and the friction from the ice apply a force of 5 N on the boy, what is the magnitude of the net force acting on him?

Answer: 70 N

4.) Four friends push on the same block in different directions. Allie pushes on the block to the north with a force of 18 N. Bill pushes on the block to the east with a force of 14 N. Chris pushes on the block to south with a force of 23 N. Debra pushes on the block to the west with a force of 20 N. Assuming it does not move vertically, in which directions will the block move?

Answer: south and west

5.)  Two teams are playing tug of war. The tables show the members of each team and how much pulling force each team member applies to the rope.

If Team A pulls to the right and Team B pulls to the left, what is the total horizontal net force applied to the rope?

Answer: 20 N to the left

I hope this helps whoever needs it :))

By Newton's second law, the net force exerted on the object makes it undergo an acceleration a such that

(2 kg) a = 5 N

so that it is accelerated a = 2.5 m/s^2.

Since the object starts with velocity 3 m/s, after 7 s its acceleration will make it speed up to

3 m/s + (2.5 m/s^2) (7 s) = 20.5 m/s

Answer:

D. Because they are using space technology on a shirt so people can wear it on earth as well

velocity I hope so oh may

50 km/h east is an example of velocity.

When an item is moving, its velocity is the rate at which its direction is changing as seen from a certain point of view and as measured by a specific unit of time. Uniform motion an object is said to have uniform motion when object cover equal distance in equal interval of time within exact fixed direction. For a body in uniform motion, the magnitude of its velocity remains constant over time.

Velocity is direction and magnitude and so 50 km/h east is an example of velocity.

50 km/h east is an example of velocity.

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Answer:

The answer is within the picture.

Explanation:

W = m g     weight of drop

W = q E

m = q E / g = = 3 e E / g

m = 3 * 1.6E-19 * 1.4E4 / 9.8 = 6.96E-16 kg

Answer:

Explanation:

Moment of inertial of a UNIFORM cylinder is ½mR²

Moment of inertial of a spherical shell is ⅔mR²

Total kinetic energy is

KE = ½mv² + ½Iω²

KE = ½m(Rω)² + ½Iω²

KE = ½mR²ω² + ½Iω²

for the cylinder

KE = ½mR²ω₁² + ½(½mR²)ω₁²

KE = ¾m0.0134²ω₁²

for the sphere

KE = ½mR²ω₂² + ½(⅔mR²)ω₂²

KE = ⅚m0.0697²ω₂²

as the KE and mass are the same

¾m0.0134²ω₁² = ⅚m0.0697²ω₂²

¾0.0134²ω₁² = ⅚0.0697²ω₂²

ω₁²/ω₂² = ⅚0.0697²/¾0.0134²

ω₁/ω₂ = 0.0697√⅚ / 0.0134√¾

ω₁/ω₂ = 5.48285455...

Answer:

Explanation:

the horizontal and vertical component's of the velocity vector:

v_x=vcos\theta=40\ \dfrac{m}{s}\cdot cos40^{\circ}=30.6\ \dfrac{m}{s},v  

x

​  

=vcosθ=40  

s

m

​  

⋅cos40  

∘

=30.6  

s

m

​  

,

v_y=vsin\theta=40\ \dfrac{m}{s}\cdot sin40^{\circ}=25.7\ \dfrac{m}{s}.v  

y

​  

=vsinθ=40  

s

m

​  

⋅sin40  

∘

=25.7  

s

m

.

Let's draw the vector (here one division corresponds to 5 m\s ):

Answer:

Which of the following has kinetic energy?

A)  A book on a shelf

B)  A girl sprinting

C)  A stretched spring

Explanation:

The average velocity is 127.27 m/s while the initial velocity is 14.55 m/s

According to Newton's law of motion:

s = [(v + u)/2]t

Where s is the distance moved = 1400 m, v is the final velocity = 240 m/s, u is the initial velocity, t is the time taken = 11 s, hence:

1400 = [(240 + u)/2)11

2800 = (240 + u)11

u + 240 = 254.55

u = 14.55 m/s

The average velocity = (v + u)/2 = (240 + 14.55)/2 = 127.27 m/s

Therefore the average velocity is 127.27 m/s while the initial velocity is 14.55 m/s

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Answer:

6767

Explanation:

Kepler's first law - sometimes referred to as the law of ellipses - explains that planets are orbiting the sun in a path described as an ellipse. ... The resulting shape will be an ellipse. An ellipse is a special curve in which the sum of the distances from every point on the curve to two other points is a constan

Charge =

(current in Amperes) x (time in seconds)

1 Ampere means 1 Coulomb per second

240 Coulombs

90 Coulombs

150 Coulombs

The answers to both are attached. Also hello to person in same class & same hw, physics 2 been a bummer but not too bad--just annoying in general.

Ampere's law allows us to find the results for the magnetic field at two distances from a system made up of two conductors:

     a) Magnetic field inside the system is:  [tex]b= \frac{\mu_o }{2\pi } \ \frac{I}{r}[/tex]  

     b) Magnetic field for the outside of the system is; b = 0

Ampere's law states that the dot product of the magnetic field times a closed path is proportional to the current within the path.

          ∫ B. ds = μ₀ I

Where bold indicates vectors, B is the magnetic field, S the closed path, muo the vacuum permittivity and I the current

a) Ask the magnetic field inside the two conductors.

Let's fix a circular path within the system, see attached, in this case the current that stops inside the path is I.

The circle length is

        s = 2π r

        B 2π r = μ₀ I

        [tex]B = \frac{\mu_o}{2\pi } \ \frac{I}{r}[/tex]  

b) Ask the magnetic field on the outside of the two wires.

Let's use a circular path in the outer part of the system, see attached, in this case with indicate that the current is the two cables is of equal magnitude and in the opposite direction the net current is zero, consequently by Ampere's law

             B=0

In conclusion using Ampere's law we can find the magnetic field for the distances of a system formed by two conductors are:

     a) Magnetic field inside the systemis:    [tex]B = \frac{\mu_o}{2\pi } \ \frac{I}{r}[/tex]  

      b) Magnetic field outside of the system is; B = 0

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