What is sieving? Give an example where this method is used. (2)​

Answer:

thermodynamics

Explanation:

The laws of thermodynamics define a group of physical quantities, such as temperature, energy, and entropy, that characterize thermodynamic systems in thermodynamic equilibrium.

Answer:

2.2 s

Explanation:

Using the equation for the period of a physical pendulum, T = 2π√(I/mgh) where I = moment of inertia of leg about perpendicular axis at one point =  mL²/3 where m = mass of man = 67 kg and L = height of man = 1.83 m, g = acceleration due to gravity = 9.8 m/s² and h = distance of leg from center of gravity of man = L/2 (center of gravity of a cylinder)

So, T = 2π√(I/mgh)

T = 2π√(mL²/3 /mgL/2)

T = 2π√(2L/3g)

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

T = 2π√(2L/3g)

T = 2π√(2 × 1.83 m/(3 × 9.8 m/s² ))

T = 2π√(3.66 m/(29.4 m/s² ))

T = 2π√(0.1245 s² ))

T = 2π(0.353 s)

T = 2.22 s

T ≅ 2.2 s

So, the period of the man's leg is 2.2 s

Answer:

(a) The height of the cliff is 9.92 m

(b) Time taken to reach the ground is 0.81 s

Explanation:

Given;

time of motion of the rock, t = 2.48 s

initial velocity of the rock, u = 8.19 m/s

(a) This is a two-way problem;

maximum upward height reached by the rock (h) + Total distance traveled downwards from the top (H).

Height of cliff = H - h

Maximum height reached by the rock;

[tex]v^2 = u^2 - 2gh\\\\0 = (8.19)^2 - (2\times 9.8)h\\\\0 = 67.08 - 19.6 h\\\\19.6h = 67.08\\\\h = \frac{67.08}{19.6} \\\\h = 3.422 \ m[/tex]

Time to reach the maximum height;

[tex]h = ut - \frac{1}{2} gt^2\\\\3.422 = 8.19t - (0.5 \times 9.8)t^2\\\\3.422 = 8.19t - 4.9t^2\\\\4.9t^2 -8.19t + 3.422 = 0\\\\This \ forms \ a quadratic \ equation ; \\\\a = 4.9, b = -8.19, c = 3.422\\\\t = \frac{-b \ \ +/- \ \ \sqrt{b^2 -4ac} }{2a} \\\\t = \frac{-(-8.19) \ \ +/- \ \ \sqrt{(-8.19)^2 -4(4.9\times 3.422)} }{2(4.9)} \\\\t = \frac{8.19 \ \ + /- \ \ \sqrt{0.0049} }{9.8} \\\\t = \frac{8.19 - 0.07}{9.8} \ \ or \ \ t = \frac{8.19 + 0.07}{9.8} \\\\t = 0.83 \ s \ \ or \ \ t = 0.84 \ s\\\\[/tex]

The time taken for rock to falll to the gound;

t₂ = 2.48 - 0.83 s

t₂ = 1.65 s

The distance traveled downwards is calculated as

H = vt + ¹/₂gt²

where;

v is the final velocity at maximum height = initial velocity when the rock starts moving downwards = 0

H =  ¹/₂gt²

H = 0.5 x 9.8 x (1.65)²

H = 13.34 m

The height of the cliff = 13.34 m - 3.422m = 9.92 m

(b) time taken to reach the ground if thrown with the same speed;

h = ut + ¹/₂gt²

9.92 = 8.19t + (0.5 x 9.8)t²

9.92 = 8.19t + 4.9t²

4.9t² +  8.19t  - 9.92 = 0

a = 4.9,  b = 8.19,  c = -9.92

use the quadratic formula;

[tex]t = \frac{-b \ \ +/- \ \ \sqrt{b^2 -4ac} }{2a} \\\\t = \frac{-8.19 \ \ +/- \ \ \sqrt{(8.19)^2 -4(4.9\times -9.92)} }{2(4.9)} \\\\t = 0.81 \ s[/tex]

Answer:

 [tex]Q=2C[/tex]

Explanation:

From the question we are told that:

Force [tex]F=10000000N[/tex]

Distance [tex]d=60m[/tex]

Where

 [tex]Q_1=Q_2[/tex]

Generally the equation for Force is mathematically given by

 [tex]F=\frac{KQ^2}{r^2}[/tex]

Where

 [tex]K=9*10^9[/tex]

Therefore

 [tex]Q^2=\frac{Fr^2}{K}[/tex]

 [tex]Q^2=\frac{10000000*60^2}{98*10^9}[/tex]

 [tex]Q=\sqrt{\frac{10000000*60^2}{9*10^9}}[/tex]

 [tex]Q=2C[/tex]

Answer:

C)12150J

Explanation:

KE = (1/2)(m)(v²)

KE = .5*30g(1kg/1000g)*(900m/s)²

KE = 12,150J

Answer:

change in the angular momentum gives a greater change in the kinetic energy since it has a quadratic dependence with the angular velocity

Explanation:

Let's write the definition of angular momentum

         L = I w

the kinetic energy is

         K = ½ I w²

         w = L / I

we substitute

       K = ½ I L² / I²

       K = L² / 2I

      K / L = w / 2

therefore a change in the angular momentum gives a greater change in the kinetic energy since it has a quadratic dependence with the angular velocity

Answer: An 8 kg book at a height of 3 m has the most gravitational potential energy.

Explanation:

Gravitational potential energy is the product of mass of object, height of object and gravitational field.

So, formula to calculate gravitational potential energy is as follows.

U = mgh

where,

m = mass of object

g = gravitational field = [tex]9.81 m/s^{2}[/tex]

h = height of object

(A) m = 5 kg and h = 2m

Therefore, its gravitational potential energy is calculated as follows.

[tex]U = mgh\\= 5 kg \times 9.81 m/s^{2} \times 2 m\\= 98.1 J (1 J = kg m^{2}/s^{2})[/tex]

(B) m = 8 kg and h = 2 m

Therefore, its gravitational potential energy is calculated as follows.

[tex]U = mgh\\= 8 kg \times 9.81 m/s^{2} \times 2 m\\= 156.96 J (1 J = kg m^{2}/s^{2})[/tex]

(C) m = 8 kg and h = 3 m

Therefore, its gravitational potential energy is calculated as follows.

[tex]U = mgh\\= 8 kg \times 9.81 m/s^{2} \times 3 m\\= 235.44 J (1 J = kg m^{2}/s^{2})[/tex]

(D) m = 5 kg and h = 3 m

Therefore, its gravitational potential energy is calculated as follows.

[tex]U = mgh\\= 5 kg \times 9.81 m/s^{2} \times 3 m\\= 147.15 J (1 J = kg m^{2}/s^{2})[/tex]

Thus, we can conclude that an 8 kg book at a height of 3 m has the most gravitational potential energy.

Answer:

The answer is "Momentum and net Energy(that contains mass)".

Explanation:

No matter which type of nuclear reaction, the momentum always is maintained. According to the formula, E = mc^2 of Einstein, energy conservation on the atomic level requires the change in mass of its core which may have been shared throughout the reaction as mass and energy, that's why we can say that the nuclei aren't fully converted into electrical energy rather rearranged and the mass could be changed and dispensed to the nucleon as energy.

Explanation:

a.)

We find the relative speed

u = vb + vc

b.)

chuck and the cart are at a rest position

mcartvc = mballvb

from part a above,

vc = u - vb

mcartu = vb(mcart + mball)

make vb the  subject of the equation

[tex]vb=\frac{mcartu}{mcart +mball}[/tex]

c.)

from anser a,

vb = u - vc

then mcart vc = mball(u-vc)

[tex]vc= \frac{Mballu}{Mcart+Mball}[/tex]

d.

Mballvb = (Mcart + Mball)vj

we make vj the subject to get her relative speed

[tex]vj=\frac{MballVb}{Mcart+Mball}[/tex]

e.

given the solution in part d above,

we have

[tex]vj=\frac{MballVb}{Mcart+Mball}[/tex]

remember,

vb = u - vc

such that

[tex]Vj = \frac{Mball(u-v)}{Mball +Mcart}[/tex]

thank you!

A thermal conductor, such as water is the type of material that is good at transferring heat. Option B is correct.

Heat conductors are substances that effectively conduct thermal energy.

The kind of substance that is effective in transferring heat is a thermal conductor, such as water.

Metals have excellent heat conductivity. Heat insulators are substances that poorly conduct thermal energy. Thermal insulators include gases like air and materials like plastic and wood.

Water conducts heat 24.17 times more quickly than air. The kind of substance that is effective in transferring heat is a thermal conductor, such as water.

Hence, option B is correct.

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The distance covered by the car for the speed of 2.40 m/s² for 15 seconds is 36 meters

To find the distance the given datas are:

Speed = 2.40 m/s²

Time = 15 seconds.

               Distance = Speed × Time.

Substituting the given datas in the formula,

Distance = 2.40 × 15

               = 36 m

The Car went at the distance of about 36 meters.

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Answer:

Explanation:

It is a case of adiabatic expansion .

[tex]T_1V_1^{\gamma-1}=T_2V_2^{\gamma-1}[/tex]

T₁ , T₂ are initial and final temperature , V₁ and V₂ are initial and final volume.

Given ,

V₂ = 3 V₁ and T₁ = 292 . γ for air is 1.4 .

[tex]( 3 )^{\gamma-1}= \frac{292}{ T_2}[/tex]

[tex]( 3 )^{1.4-1}= \frac{292}{ T_2}[/tex]

1.552 = 292 / T₂

T₂ = 188 K .

им putins брат, почему вы обманываете нашу систему образования, Это теперь запрещено в России.

Answer:

1.32kgm/s

Explanation:

use the formula: p=mv

The momentum of a lab cart  = -1.32 kg m/s

It is measure of the inertia of a body/ object .It can be calculated by multiplying mass with velocity .

General formula for momentum = M = m * v

given

mass = 0.60  kg

speed = 2.2 m/s

velocity = - 2.2 m/s ( answer is in negative , since mass is a scaler quantity  but velocity is a vector quantity  hence ,  velocity can be negative )

momentum = mass * velocity

                   = 0.60 * (-2.2 ) = -1.32 kg m/s

The momentum of a lab cart  =c) -1.32 kg m/s

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Answer:

The rate of change of distance between the two ships is 18.63 km/h

Explanation:

Given;

distance between the two ships, d = 140 km

speed of ship A = 30 km/h

speed of ship B = 25 km/h

between noon (12 pm) to 4 pm = 4 hours

The displacement of ship A at 4pm = 140 km - (30 km/h x 4h) =

140 km - 120 km = 20 km

(the subtraction is because A is moving away from the initial position and the distance between the two ships is decreasing)

The displacement of ship B at 4pm = 25 km/h x 4h = 100 km

Using Pythagoras theorem, the resultant displacement of the two ships at 4pm is calculated as;

r² = a²   +  b²

r² = 20²  +  100²

r = √10,400

r = 101.98 km

The rate of change of this distance is calculated as;

r² = a²   +  b²

r = 101.98 km, a = 20 km, b = 100 km

[tex]2r(\frac{dr}{dt} ) = 2a(\frac{da}{dt} ) + 2b(\frac{db}{dt} )\\\\r(\frac{dr}{dt} ) = a(\frac{da}{dt} ) + b(\frac{db}{dt} )\\\\101.98(\frac{dr}{dt} ) = 20(-30 ) + 100(25 )\\\\101.98(\frac{dr}{dt} ) = -600 + 2,500\\\\101.98(\frac{dr}{dt} ) = 1900\\\\\frac{dr}{dt} = \frac{1900}{101.98} = 18.63 \ km/h[/tex]

Answer:

In some situations, matter demonstrates wave behavior rather than particle behavior. This is best illustrated by which phenomenon is:

C. Interference patterns of electrons.

Answer:

C. Interference patterns of electrons

Explanation:

1.9If an EM wave has a wavelength of 595 nm, what is its frequency9 x 10^-6 Hz

Explanation:

aah cmmon just come over to my meet

Answer:

20 characters

Explanation:

The bottle is squeezed, when a bottle with a reservoir is squeezed, is the fluid will come up through the bottom of the reservoir. Thus, the correct option is D.

A reservoir is an artificial lake where the water is stored. Most of the reservoirs are formed through the construction of the dams across major rivers. A reservoir can also be formed from a natural lake whose outlet has been dammed to control the water level in that.

When we squeeze an open bottle which is filled with water, the water in the bottle will spill out. When we squeeze a bottle, the material collapses where we squeeze it, however it expands in other areas, resulting in a constant volume. If the volume is constant, then we would think that the water should not spill out.

Therefore, the correct option is D.

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Answer:

v= IR then you can R= v/I 9v÷0.002 = 450 Ohms

Answer:

The acceleration will be "-5.12 km/s²".

Explanation:

The given values are:

This might be defined as a continuous inanimate object at either the speed between such organization as well as the Klingon boat (54 - 22) km/s.  

The values given in the question are:

= 110 km

Final velocity will be:

= 0

By using to the third equation of motion, we get

⇒ [tex]v^2=u^2+2as[/tex]

     [tex]0=(54-22)^2+2\times a\times 100[/tex]

     [tex]0=(32)^2+2\times a\times 100[/tex]

     [tex]0=1024+2\times a\times 100[/tex]

     [tex]0=1024+200a[/tex]

     [tex]-1024=200a[/tex]

             [tex]a=-\frac{1024}{200}[/tex]

                [tex]=-5.12 \ km/s^2[/tex]

Answer:

Many people are not clear about the difference between our Solar System, our Milky Way Galaxy, and the Universe.

Let’s look at the basics.

Our Solar System consists of our star, the Sun, and its orbiting planets (including Earth), along with numerous moons, asteroids, comet material, rocks, and dust. Our Sun is just one star among the hundreds of billions of stars in our Milky Way Galaxy. If we shrink the Sun down to smaller than a grain of sand, we can imagine our Solar System to be small enough to fit onto the palm of your hand.  Pluto would orbit about an inch from the middle of your palm.

Artist diagram of Milky Way galaxy

On that scale with our Solar System in your hand, the Milky Way Galaxy, with its 200 – 400 billion stars, would span North America (see the illustration on the right). Galaxies come in many sizes. The Milky Way is big, but some galaxies, like our Andromeda Galaxy neighbor, are much larger.

The universe is all of the galaxies – billions of them! NASA’s telescopes allow us to study galaxies beyond our own in exquisite detail, and to explore the most distant reaches of the observable universe. The Hubble Space Telescope made one of the deepest images of the universe, called the Hubble Extreme Deep Field (image at the top of this article). Soon the James Webb Space Telescope will be exploring galaxies forming at the very beginning of the universe.

You are one of the billions of people on our Earth.  Our Earth orbits the Sun in our Solar System.  Our Sun is one star among the billions in the Milky Way Galaxy.  Our Milky Way Galaxy is one among the billions of galaxies in our Universe.  You are unique in the Universe!

You can observe objects in our solar system and even see other galaxies at a star party near you-and rest assured that everything you are seeing  is a part of the same universe as you!

Explanation:

A solar system is the system of celestial bodies built around a central star, the Sun. All of the system bodies, be they dwarf planets, small bodies and large planets, are held in a gravitational bond around the central star. Our solar system has eight large planets:

Four inner planets which are terrestrial, made entirely of rock and metal: Mars, Mercury, Earth and Venus;

Four outer planets which are gas and ice giants: Jupiter and Saturn (composed entirely of helium and hydrogen), Uranus and Neptune (composed of ices such as water, ammonia and methane).

The solar system also contains asteroid belts and the natural satellites of some of the planets. The trans-Neptunian region has the Kuiper belt, home to several dwarf planets, Pluto among them. Our solar system is located on the Orion Arm and is part of the Milky Way Galaxy. It was formed 4.6 billion years ago.

A galaxy is made out of billions of stars and their solar systems, held together by gravity, with a super- massive black hole at the center. Our Solar System is called the Milky Way; it is a spiral galaxy and the black hole in the center is called Sagittarius A*. Apart from the spiral shape, galaxies can also be elliptical or irregular in form. Galaxies gather in groups, clusters and super-clusters and there are billions of Galaxies in the Universe.

Some of these other galaxies are visible to the naked eye on a dark night and from places away from artificial light sources. The Andromeda Galaxy is the most recorded one throughout time and all over the world, its existence having been noted since the 10th century by Persian astronomer Al-Sufi, and having been the object of debate among other great thinkers up to the moment when the technology caught up to the discourse.

Solar System vs Galaxy

So what is the difference between a solar system and a galaxy?

A solar system represents the group of planets gravitationally bound to the central star. A galaxy has billions of stars and their solar systems. This difference in size is not only visible in the number of stars it is made out of, but also by how long it takes to cross it. It takes one light year to cross our solar system, and 100,000 light years to cross the galaxy.

While the biggest thing inside a solar system is the central sun, the biggest thing inside a galaxy is a massive black hole. The planets in a solar system orbit the sun, which is at the center, and the Sun, in turn, orbits the center of the Milky Way.

Comparison Chart

Solar system Galaxy

A group of planets orbiting the central sun A group of planetary systems whose central Suns are orbiting the center of the Galaxy

Gravitationally bound Gravitationally bound

Can be crossed in 1 light year Can be crossed in 100,000 light years

Most of the system mass is taken up by the central sun It hosts a super massive black hole, Sagittarius A*

More solar systems make up galaxies More galaxies make up the Universe

Answer:

Note the word "circular".

Meaning the area would be found using that of a circle = πr²

Recall

Pressure = Force/Area

Area = π x 0.5² = 0.785m²

Pressure = 20/0.785

= 25pa ( to the nearest whole number)

Pressure = Force/Area

As the table is circular, we have to use the formula of area of circle;

= πr²

= 3.14 × 0.5 × 0.5

= 3.14 × 0.25

= 0.785 m²

Put the values of force and area in formula;

= 20/0.785

= 20000/785

= 25.45 Pa

= 25 Pa (Approx)

Answer:

the magnetic field is leaving the sheet

Explanation:

The magnetic force is given by the expression

        F = q v x B

where bold letters indicate vectors, the modulus of this expression is

       F = q v B sin θ

the direction of the force is given by the right hand rule, for a positive charge

the thumb indicates the direction of the speed, in this case from right to left

the palm the direction of the force, in our case upwards

the fingers extended the direction of the magnetic field, this case after fixing the other two components it points out of the blade

In short the magnetic field is leaving the sheet

Answer:

The electric force will also double.

When the test charge q is double the change in magnitude of the electric force is that it also gets doubled.

Electric force is defined as force between the chages which is directly proportional to the product of charges and inversely proportional to the square of the distance between them. The electric force is a vector quantity, It have magnitude as well as direction.

Electric force = k*Q*q/r²

The electric field is defined as the electric force per unit charge. The electric field is a vector quantity.

Electric field = Electric force / test charge

Electric field = k*Q/r²

Given that in question there is the test charge, q for electric field and the source charge Q when the test charge q will become 2q then electric force is,

Electric force = kQ(2q)/r²

So, the magnitude of the electric force is increased by twice when the test charge will become 2q.

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Answer:

Energy = 1.38*10^13 J/mol

Explanation:

Total number of proton in F-19 = 9

Total number of neutron in F-19 = 10

Expected Mass of F-19  

= 9*1.007 + 10*1.008 = 19.152 u

Actual  mass of F-19 = 18.998 u

Energy of one particle of F-19 = 931.5*Δm = 931.5*(19.152-18.998)

= 143.234 MeV

Energy of one mole of F-19 = 143.234*10^6*1.6*10^-19*6.022*10^23  

= 1.38*10^13 J/mol

a) v = 1.94 × 10^5 m/s

b) Ms = 2.09 × 10^24 kg

Explanation:

Given:

m = 0.257M (M = mass of earth = 5.972×10^24 kg)

= 1.535×10^24 kg

r = 7.18×10^9 m

T = 2.7 days × (24 hr/1 day) × (3600 s/1 hr)

= 2.3328×10^5 s

a) To find the orbital speed of the planet, we need to find the circumference of the planet's orbit first:

C = 2×(pi)×r

= 2(3.14)(7.18×10^9m)

= 4.51×10^10 m

The orbital speed v is then given by

v = C/T

= (4.51×10^10 m)/(2.33×10^5 s)

= 1.94 × 10^5 m/s

b) We know that centripetal force Fc is given by

Fc = mv^2/r

where v = orbital speed

r = average orbital radius

m = mass of planet

We also know that the gravitational force FG between the star K2-116 and the planet is given by

FG = GmMs/r^2

where m = mass of planet

Ms = mass of star K2-116

r. = average orbital radius

G = universal gravitational constant

= 6.67 × 10^-11 m^3/kg-s^2

Equating Fc and FG together, we get

Fc = FG

mv^2/r = GmMs/r^2

Note that m and one of the r's get cancelled out so we are left with

v^2 = GMs/r

Solving for the mass of the star Ms, we get

Ms = rv^2/G

=(7.18 × 10^9 m)(1.94 × 10^5 m/s)^2/(6.67 × 10^-11 m^3/kg-^2)

= 2.09 × 10^24 kg

Answer:

0.0872

Explanation:

the solution to the problem can be found in the attachment section. Please go through and feel free to ask your doubts.

Answer:

lungs. hopes this helps

Answer:

C.

Explanation:

Kinetic Energy is defined as something that possesses energy because it is in motion. Potential Energy is something that is at rest that ha the potential to have kinetic energy when it is set in motion.

All of these other choices are in motion, hence, they have kinetic energy. The jar is at rest, so it has potential energy. All of those objects were are rest at one point and had kinetic energy, before they started moving. If the jar was to fall off the shelf, its potential energy would transfer to kinetic energy.

Answer:

C. Glass jar sitting of a shelf

Explanation:

Because everything else is full of kinetic energy but moving, so the only item not using kinetic energy is the jar.