You are pulling with 57 N on a heavy bookshelf, but the bookshelf doesn't move. What is the force of static friction in Newtons acting on the bookshelf?​

Answer:

Both are electromagnetic waves

Explanation:

Hope this helped!!

Answer:

Natural selection.

Explanation:

Natural selection can be defined as a biological process in which species of living organisms having certain traits that enable them to adapt to environmental factors such as predators, competition for food, climate change, sex mates, etc., tend to survive and reproduce, as well as passing on their genes to subsequent generations.

Simply stated, natural selection entails the survival of the fittest. Therefore, the species that are able to adapt to the environment will increase in number while the ones who can't adapt will die and go into extinction.

On the other hand, artificial selection is also known as selective breeding and it is a process that involves humans (breeders) selecting the animal or plant with desirable traits in order to reproduce favorable offspring having phenotypic traits.

Answer: Mount Nevado Huascarán

Explanation: Mount Nevado Huascarán in Peru has the lowest gravitational acceleration, at 9.7639 m/s2, while the highest is at the surface of the Arctic Ocean, at 9.8337 m/s2

Answer:

The forward motion of a body in space, such as a planet or moon, and the pull of gravity on it from another body in space.

Explanation:

Earth and many other bodies—including asteroids, comets, and the other planets—move around the sun in curved paths called orbits. Generally, the orbits are elliptical, or oval, in shape. Because of the sun’s relatively strong gravity, Earth and the other bodies constantly fall toward the sun, but they stay far enough away from the sun because of their forward velocity to fall around the sun instead of into it. As a result, they keep orbiting the sun and never crash to its surface. The motion of Earth and the other bodies around the sun is called orbital motion. Orbital motion occurs whenever an object is moving forward and at the same time is pulled by gravity toward another object.

Answer:

R =V/ I =12.6 ÷ 0.53= 27.77 ohm

Answer:

Wheelbarrows, fishing rods, shovels, brooms, arms, legs, boat oars, crow bars, and bottle openers are all examples of levers. Levers may be one of the most used simple machine. As with all simple machines like the lever, they are designed to help make work easier to do.

Explanation:

Answer:

Wheelbarrows- This tool/device is used for a variety of things, such as moving rock, mulch or compost to the garden, moving trees or large shrubs from one spot to another, hauling bricks, disposing of garden debris, for mixing concrete or fertilizers, and even used on farms for mucking horse stalls. The work you do is pushing it whcih also goes along with the montion you will see, forward motion.

Explanation:

Answer:

Particles in agas are well separated with no regular arrangement. liquid are close together with no regular arrangement. solid are tightly packed, usually in a regular pattern.

Explanation:

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Answer:

the only correct answer is: Photons of lower-frequency light don't have enough energy to eject an electron

Explanation:

This question is in the model of the photoelectric effect, where some electrons are expelled from the metal by the action of a ray of light.

This effect was explained by Einstein supposes that the light rays are formed by photons and the energy of these photons is given by the Planco relation

           K = h f - Ф

where K is the kinetic energy of the ejected electrons and Ф is the work function, it keeps the electrons inside the material.

When analyzing this expression there is a minimum frequency (threshold) for which K = 0

           hf = Ф

Below this frequency the photons in the light beam do not have the energy to expel the electrons from the material.

Let's examine the answers

a) True. You agree with the above

b) False. The analysis is in terms of individual shock

c) False. The expulsion does not have to do with the number of photons but with the energy of each one

therefore the only correct answer is: Photons of lower-frequency light don't have enough energy to eject an electron

Answer:

[tex]0.059\ \text{m/s}[/tex]

Explanation:

[tex]m_1[/tex] = Mass of bullet = 4.2 g

[tex]u_1[/tex] = Initial velocity of bullet = 0

[tex]m_2[/tex] = Mass of hunter with rifle = 69.5 kg

[tex]u_2[/tex] = Initial velocity of hunter with rifle

[tex]v_1[/tex] = Final velocity of the bullet = 970 m/s

[tex]v_2[/tex] = Final velocity of the hunter with the rifle

As the momentum of the system is conserved we have

[tex]m_1u_1+m_2u_2=m_1v_1+m_2v_2\\\Rightarrow v_2=\dfrac{m_1u_1+m_2u_2-m_1v_1}{m_2}\\\Rightarrow v_2=\dfrac{0-0-0.0042\times 970}{69.5}\\\Rightarrow v_2=-0.059\ \text{m/s}[/tex]

The recoil speed of the hunter is [tex]0.059\ \text{m/s}[/tex] in the opposite direction of the bullet.

Answer:

Exposing the testicles to high temperatures could lead to problems

    with producing sperm.

Explanation:

got it correct on the edge unit test review

Brent's doctor most likely recommended that he avoid hot baths because exposing the testicles to high temperatures could lead to problems with producing sperm.

The sperm is the male reproductive cell that is produced in the testes and stored in the epididymis.

The testicles (testes) of the male is located outside the body as the temperature of the body is too high for the viability of the sperm.

Therefore, exposing the testicles to high temperatures could lead to problems with producing sperm.

Learn more about sperm here:

https://brainly.com/question/25282799

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Answer: The Answer is C

Explanation:

I just got this question and took a guess I got it correct lol. Higher potential energy and energy is released.

The statement which best describes the total energy change of the system is energy is absorbed, and the reactants have higher potential energy.

Potential energy is the energy which a body posses because of its position. The potential energy is the stored energy.

The energy diagram shows the changes in energy during a chemical reaction.

Potential energy and Reaction progress are shown in the problem. The reactants are the substance which reacts and form one or more than one product.

The reactants in a chemical reaction increases the potential energy for the reaction.



Thus, the statement which best describes the total energy change of the system is energy is absorbed, and the reactants have higher potential energy.

Learn more about the potential energy here;

https://brainly.com/question/15896499



Answer:

The greater the weight of the person, the more static friction.

Explanation:

USATestPrep

b.gravity have a great day:)

Answer:

who will solve environmental problems, who is responsible for environmental problems, and who pays the cost of implementing solutions

Explanation:

Answer:

the refracted rays neither converge nor diverge. After refracting, the light rays are traveling parallel to each other and cannot produce an image.

Explanation:

Answer:

dolphin and wolf

Explanation:

the sharks jaw is way to small for it and is shaped differently

Answer:

 f = 7.9487 10¹³ Hz

Explanation:

The photoelectric effect was correctly explained by Einstein assuming that the radiation is composed of photons, which behave like particles.

           hf = K + Ф

It indicates the frequency and the kinetic energy, let's look for the work function

          Ф = hf - K

let's reduce the magnitudes to the SI system

          K = 0.332 eV (1.6 10⁻¹⁹ J / 1 eV) = 0.5312 10⁻⁻¹⁹ J

let's calculate

          Ф = 6.63 10⁻⁻³⁴  6.64 10¹¹ - 0.5312 10⁻¹⁹

          Ф = 4.40 10⁻²² - 0.5312 10⁻¹⁹

          Ф = 5.27 10⁻²⁰ J

for the minimum frequency that produces photoelectrons, the kinetic energy is zero

           hf = Ф  

           f = Ф / h

           f = 5.27 10⁻²⁰ / 6.63 10⁻³⁴

           f = 7.9487 10¹³ Hz

Answer:

[tex]\mathbf{\alpha = 25.88 \ rad/s^2 }[/tex]

Explanation:

Consider the force due to friction:

[tex]F = \mu_kN -------- (1)[/tex]

where;

N = normal reaction

[tex]\mu_k[/tex] = coefficient of kinetic friction.

Via the horizontal direction, the forces of equilibrium are:

[tex]\sum F_x = \sum(F_x) _{eff} \\ \\ N- F_{AB} \ cos \theta = 0 \\ \\ F_{AB} \ cos \theta = N ------ (2)[/tex]

where;

[tex]\theta[/tex] = angle of AB is associated with the horizontal;

[tex]F_{AB}[/tex] = force exerted by AB

Let's take a look at the equilibrium of forces along the vertical direction.

[tex]\sum F_y = \sum (F_y)_{eff} \\ \\ F+F_{AB} sin \theta - W = 0\\ \\ \mu_k N + F_{AB} sin \theta -mg =0 \\ \\ F_{AB} sin \theta = mg - \mu_kN-------(3)[/tex]

By dividing (3) by (2), we get:

[tex]\dfrac{F_{AB} sin \theta }{F_{AB} cos \theta} = \dfrac{mg - \mu_k N}{N} \\ \\ tan \theta = \dfrac{mg-\mu_kN}{N} \\ \\ Ntan \theta = mg - \mu_kN \\ \\ N(tan \theta + \mu_k ) = mg \\ \\ N = \dfrac{mg}{tan \theta + \mu_k}[/tex]

By replacing the obtained value of N into:

[tex]F = \mu_k N[/tex]

we have:

[tex]F = \mu_k (\dfrac{mg}{tan \theta + \mu_k}) \\ \\ \\ F = \dfrac{mg \mu_k}{tan \theta + \mu_k}[/tex]

Moment about center A can be expressed as:

[tex]\sum M_A = \sum (M_A) _{eff} \\ \\ Fr = I \alpha\\ \\ \alpha = \dfrac{Fr}{I}[/tex]

where;

[tex]\alpha[/tex] = angular acceleration of the disc

I = mass moment of inertia

r = radius of disc

By replacing F and I; ∝ becomes:

[tex]\alpha = \dfrac{\bigg( \dfrac{mg \mu_k}{tan \theta + \mu_k} \bigg) r}{\dfrac{1}{2}mr^2}[/tex]

[tex]\alpha = \dfrac{2g}{r} \dfrac{\mu_k}{tan \ \theta + \mu_k}------- (4)[/tex]

where;

g = 9.8 m/s²

r = 0.18 m

[tex]\mu_k = 0.54[/tex]

θ = 60°

[tex]\alpha = \dfrac{2(9.8)}{0.18} (\dfrac{0.54}{tan \ 60+ 0.54})[/tex]

[tex]\mathbf{\alpha = 25.88 \ rad/s^2 }[/tex]

Answer:

K_{total} = 19.4 J

Explanation:

The total kinetic energy that is formed by the linear part and the rotational part is requested

         [tex]K_{total} = K_{traslation} + K_{rotation}[/tex]

let's look for each energy

linear

        [tex]K_{traslation}[/tex] = ½ m v²

rotation

        [tex]K_{rotation}[/tex] = ½ I w²

the moment of inertia of a solid sphere is

       I = 2/5 m r²

we substitute

       [tex]K_{total}[/tex] = ½ mv² + ½ I w²

angular and linear velocity are related

           v = w r

we substitute

           K_{total} = ½ m w² r² + ½ (2/5 m r²) w²

           K_{total} = m w² r² (½ + 1/5)

           K_{total} = [tex]\frac{7}{10}[/tex] m w² r²

let's calculate

           K_{total} = [tex]\frac{7}{10}[/tex]   6.40 16.0² 0.130²

           K_{total} = 19.4 J

Answer:

Explanation:

The energy transfer are not changing in kinetic energy. They are changes in bonding energy between the molecules.

Answer:

The correct response will be "13.755 kN".

Explanation:

According to the question,

The given values are:

a = 300 mm

i.e.,

  = 0.3 cm

b = 200 mm

i.e.,

  = 0.2 dm

Internal pressure,

[tex]P_{in}=100[/tex]

Now,

The area of the elliptical shape window will be:

⇒  [tex]A = \pi ab[/tex]

On substituting the values, we get

⇒      [tex]=3.14\times 0.300\times 0.200[/tex]

⇒      [tex]=0.1885 \ m^2[/tex]

By using the table,

At 10 km, the atmospheric pressure will be

⇒  [tex]p_o=27.03 \ kPa[/tex]

Now,

The outward force will be:

⇒  [tex]F_{net}=p_{in}A-p_{0}A[/tex]

⇒          [tex]=(p_{in}-p_{0})A[/tex]

⇒          [tex]=(100-27.03)\times (0.1885)[/tex]

⇒          [tex]=13.755 \ kN[/tex]

Answer:

Explanation: Magnets can be used in space. ... Magnets don't need gravity or air. Instead, their power comes from the electromagnetic field they generate all by themselves. One class of magnets, called electromagnets, does need electricity to work.

Answer:

magnets work due to a magnetic field and attract or repel an electrically charged or magnetic objects

Explanation:

its magnetism works due to alignment of atoms in a magnetic object

Answer:

Magnet withe competitive prices and high quality they offer custom-made magnets in defferent form and made with defferent materials grades

Explanation:

Sana makatolong

Answer:

La velocidad de la luz en el vacío es una constante universal con el valor de 299 792 458 m/s (186 282,397 mi/s),​​aunque suele aproximarse a 3·108 m/s. Se simboliza con la letra c, proveniente del latín celéritās (en español, celeridad o rapidez).

¿Cuál es la consecuencia que a velocidad de la luz sea constante?

Respuesta. En modificaciones del vacío más sutiles, como espacios curvos, efecto Casimir, poblaciones térmicas o presencia de campos externos, la velocidad de la luz depende de la densidad de energía de ese vacío.

Answer:

[tex]\underline{\textsf{\textbf{Answer -}}}[/tex]

No & Yes - the case depends actually.

You can't make the velocity zero and expect to stay in space. you will need to constantly fire the engine to hold youself in position (this is possible, until you run out of fuel).

Yes, it is possible to fire the engine and lift off earth into space, and then fire in the opposite direction to earths movement until you are still, relative to the sun. But if you now turn the engine off, the suns gravity will pull you down and directly into the sun.

its the earths forward motion that prevents it falling into the sun

Answer:

No & Yes - the case depends actually.

You can't make the velocity zero and expect to stay in space. you will need to constantly fire the engine to hold youself in position (this is possible, until you run out of fuel).

Yes, it is possible to fire the engine and lift off earth into space, and then fire in the opposite direction to earths movement until you are still, relative to the sun. But if you now turn the engine off, the suns gravity will pull you down and directly into the sun.

its the earths forward motion that prevents it falling into the sun

Answer:

a) 1.542 m/s

b) t = 38.91 mins

Explanation:

Given data:

Diameter of tank ( D ) = 3 m

height of tank ( initial ) ( h =  z1 ) = 2m

Diameter of sharp edged orifice = 0.1 m

pipe length ( L ) = 100 m

coefficient of friction of pipe ( f ) = 0.015

∝1 = ∝2 = 1

A) calculate initial velocity from the tank

since the fluid is open to the atmosphere ; p1 = p2 = Patm ( atm pressure )

the initial velocity of the tank can be determined with the equation below

V = [tex]\sqrt{\frac{2gZ1}{1 + f \frac{L}{d} + K _{L} } }[/tex]  ---- ( 1 )

where : Z1 = 2m , f = 0.015, L = 100m ,  Kl = 0.5m , d = 0.1 m , g = 9.81m/s^2

input given values into equation 1 above

V = 1.542 m/s

b) Determine time required to empty tank

Given velocity = [tex]\sqrt{\frac{2gZ1}{1 + f \frac{L}{d} + K _{L} } }[/tex]  and Flow rate = [tex]\sqrt{\frac{2gZ1}{1 + f \frac{L}{d} + K _{L} } }* \frac{\pi }{4} *d^2[/tex]

differentiate the flow rate ( dt ) and then integrate the equation to get the required expression

t = [tex]\frac{2D^2}{d^2} \sqrt{\frac{(1+f\frac{L}{d}+K_{L})Z_{1} }{2g} }[/tex]   -------- ( 2 )

where : : Z1 = 2m , f = 0.015, L = 100m ,  Kl = 0.5m , d = 0.1 m , g = 9.81m/s^2, D = 3m

input values into equation 2

t = 38.91 mins

Answer:

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Answer:

Continental drift describes one of the earliest ways geologists thought continents moved over time. Today, the theory of continental drift has been replaced by the science of plate tectonics. 

The theory of continental drift is most associated with the scientist Alfred Wegener. In the early 20th century, Wegener published a paper explaining his theory that the continental landmasses were “drifting” across the Earth, sometimes plowing through oceans and into each other. He called this movement continental drift. 

Answer:

[tex]1.302\ \text{kg/s}[/tex]

Explanation:

[tex]\rho[/tex] = Density of water = [tex]1\ \text{kg/L}[/tex]

[tex]dV[/tex] = Change in volume = [tex]220\times 0.355\ \text{L}[/tex]

[tex]dt[/tex] = Time elapsed = 1 minute = 60 seconds

Mass flow rate is given by

[tex]\dot{m}=\rho\dfrac{dV}{dt}\\ =1\times \dfrac{220\times 0.355}{60}\\ =1.302\ \text{kg/s}[/tex]

The mass flow rate is [tex]1.302\ \text{kg/s}[/tex].