In the United States, household electric power is provided at a frequency of 60 HzHz, so electromagnetic radiation at that frequency is of particular interest. On the basis of the ICNIRP guidelines, what is the maximum intensity of an electromagnetic wave at this frequency to which the general public should be exposed

Answer:

Silver has greater electronegativity (pull on electrons) than copper, so it will be reduced rather than oxidized. Silver ions will plate out on copper metal. Sir the coating of iron with copper surface can be referred as IRON-COPPER PLATING.

Explanation:

Iron is used for the electroplating of so copper because iron falls above copper in the electrochemical series whereas silver will fall off below the copper in electrochemical series that makes it not reliable for the electroplating purpose

Answer:

diameter     of       the  wire   =  0.05  in  =0.05 /12   =4.167 *10 ^-3  ft

area   of cross  section    of the  wire  = A =  22/7 *  ( d /2 ) ^2  =0.786 *  (  4.167 *10 ^-3 ) ^2  =1.365 *10 ^-5  ft2  

E  =...

Explanation:

Answer:

The mass of the rod is 16 kg.

Explanation:

Given that,

The length of a rod, L = 3 m

The moment of inertia of the rod, I = 12 kg-m²

We need to find the mass of the rod. The moment of inertia of the rod of length L is given by :

[tex]I=\dfrac{ML^2}{12}[/tex]

Where

M is mass of the rod

[tex]M=\dfrac{12I}{L^2}\\\\M=\dfrac{12\times 12}{(3)^2}\\\\M=16\ kg[/tex]

So, the mass of the rod is 16 kg.

poste en français s’il vous plaît

Answer:

The answer is letter B hope it helps

Answer:

High frequency sound causes two types of health effects: on the one hand objective health effects such as hearing loss (in case of protracted exposure) and on the other hand subjective effects which may already occur after a few minutes: headache, tinnitus, fatigue, dizziness and nausea.

Answer:

the velocity of the big fish after the launch is 6 m/s.

Explanation:

Given;

mass of the big fish, m₁ = 5 kg

velocity of the big fish, u₁ = 8 m/s

mass of the small fish, m₂ = 1 kg

velocity of the small fish, u₂ = -4 m/s

Let the final velocity of the big fish after launch = v

Apply the principle of conservation linear momentum;

m₁u₁ + m₂u₂ = v(m₁ + m₂)

5 x 8   + 1 x (-4) = v(5 + 1)

40 - 4 = 6v

36 = 6v

v = 36/6

v =  6 m/s.

Therefore, the velocity of the big fish after the launch is 6 m/s.

Answer:

true

Explanation:

normally -No system has ever performed well with one object.

A system must contain more than one object is a true statement.

A system is a group of interacting or interrelated objects that act according to a set of rules to form a unified whole.

Normally, no system has ever performed well with one object.

To learn more about System here

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Answer:

The velocity of the center of mass of the two-ball system is 13.1 m/s.

Explanation:

Given;

mass of the first ball, m₁ = 0.5 kg

mass of the second ball, m₂ = 0.25 kg

initial velocity of the second ball, u₂ = 19.6 m/s

At the highest point the velocity of the second ball, v₂ = 0

The highest point reached by the second ball is calculated as;

v₂² = u₂² - 2gh

0 = u₂² - 2gh

2gh = u₂²

h = u₂² / 2g

h = (19.6²) / (2 x 9.8)

h = 19.6 m

The final velocity of the first ball when it had traveled 19.6 m down;

v₁² = u₁² + 2gh

v₁² = 0 + 2gh

v₁ = √2gh

v₁ = √(2 x 9.8 x 19.6)

v₁ = 19.6 m/s

The velocity of the center of mass of the two-ball system is calculated as;

[tex]v = \frac{m_1v_1 \ + \ m_2v_2}{m_1 \ + \ m_2} \\\\v = \frac{0.5\times 19.6 \ + \ 0.25\times 0}{0.5 \ + \ 0.25} \\\\v = 13.1 \ m/s[/tex]

Answer:

B. False

A concave mirror and a converging lens will only produce a real image if the object is located beyond the focal point.

~Hoped this helped~

~Brainiliest?~

Answer:

PE = 0.73J

Explanation:

Remember that in conservative spring systems,

Total energy = potential + kinetic energy.

On the y-axis lies the kinetic energy and the question asks for the potential energy.

PE + KE must always equal the same result.

In this case, KE + PE = 1

So rearranging the equation,

PE = 1 - KE

KE = 0.27 (as we can see from the graph)

Therefore,

PE = 1 - 0.27 = 0.73J

Bonus tip: The graphs of potential and kinetic energy will look the exact opposite in this case. When the KE graph is at 0J, the PE graph is at 1J and vice versa. And they always cross over at 0.5J

Answer:

[tex]1.714\ \text{A}[/tex]

Explanation:

F = Magnetic force = 0.018 N

B = Magnetic field = 0.03 T

L = Length of wire = 35 cm

[tex]\theta[/tex]  = Angle between current and magnetic field = [tex]90^{\circ}[/tex]

Magnetic force is given by

[tex]F=IBL\sin\theta\\\Rightarrow I=\dfrac{F}{BL\sin\theta}\\\Rightarrow I=\dfrac{0.018}{0.03\times 35\times 10^{-2}\times \sin90^{\circ}}\\\Rightarrow I=1.714\ \text{A}[/tex]

The magnitude of the current is [tex]1.714\ \text{A}[/tex].

Answer: ?

Explanation:

Answer:

720

Explanation:

Answer:

[tex]\tau=0.03\ N-m[/tex]

Explanation:

Given that,

Force acting, F = 6N

The radius of the path, [tex]r=10^{-2}\ m[/tex]

Angle, [tex]\theta=30^{\circ}[/tex]

We need to find the amount of torque acting on the object. The formula for torque is given by :

[tex]\tau=Fr\sin\theta\\\\\tau=6\times 10^{-2}\times \sin(30)\\\\\tau=0.03\ N-m[/tex]

So, the required torque is equal to 0.03 N-m.

Answer:

[tex]2625.156\ \text{N}[/tex]

Explanation:

Dimensions of mattress 100 cm by 194 cm by 14 cm

[tex]m_m[/tex] = Mass of mattress = 4 kg

[tex]\rho[/tex] = Density of water = [tex]1000\ \text{kg/m}^3[/tex]

g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]

Volume of mattress

[tex]V=100\times 194\times 14=271600\ \text{cm}^3=0.2716\ \text{m}^3[/tex]

Weight of water displaced is equal to the buoyant force

Mass of water

[tex]m=\rho V\\\Rightarrow m=1000\times 0.2716\\\Rightarrow m=271.6\ \text{kg}[/tex]

Mass of person would be

[tex]m_p=m-m_m=271.6-4\\\Rightarrow m_p=267.6\ \text{kg}[/tex]

Weight of the person would be

[tex]w=m_pg\\\Rightarrow w=267.6\times 9.81\\\Rightarrow w=2625.156\ \text{N}[/tex]

The air mattress could hold a person that weighs up to [tex]2625.156\ \text{N}[/tex].

Answer:

B: Amplitude

Explanation:

When a wave travels from one medium to the other from an angle, the things that change are amplitude, wavelength, intensity and velocity.

The frequency doesn't change because the frequency depends upon the source of the wave and not the medium by which the wave is propagated.

Answer:

The angle

Explanation:

Answer:

2π/[28 x (10^-3)]

Explanation:

Angular speed : ω=2π/T

T = 28ms = 28 x (10^-3) s

Angular speed = 2π/[28 x (10^-3)]

Answer:

See explanation

Explanation:

Let us recall that temperature is a measure of the average kinetic energy of the molecules of a body.The higher the temperature, the higher the kinetic energy of the molecules of the body.

As temperature decreases, the kinetic energy of the molecules of a substance also decreases rapidly and the magnitude of intermolecular interaction between molecules of the substance increases.

Hence, as argon gas is cooled from 20°C to -190°C the kinetic energy of the gas molecules decreases an the magnitude of intermolecular interaction increases hence the gas changes into liquid and subsequently changes into a solid at -190°C.

Answer:

   ΔT = [tex]\frac{\Delta K}{(m_1+m_2) c_e }[/tex]    

Explanation:

This is an interesting problem, no data is given, so the result is a general expression.

Suppose that the disks are initially rotating with angular velocity w₁ and w₂, as well as that they have radii r₁ and r₂ and masses m₁ and m₂

we start the problem finding odl final angular velocity of the discs together, for this we define a system formed by the two discs, in this case the torques during the collision are internal and the angular momentum is conserved

initial instant. Just before the crash

           L₀ = L₁ + L₂

with

           L₁ =  I₁ w₁

the moment of inertia of a disc with an axis passing through its center is

           I₁ = ½ m₁ r₁²

we substitute

           I₀ = ½ m₁ r₁² w₁ + ½ m₂ r₂² w₂

final instant. Right after the crash

         L_f = I w

in angular momentum it is a scalar quantity, so it is additive

         I = I₁ + I₂

angular momentum is conserved

         L₀ = L_f

         I₁ w₁ + I₂ w₂ = I w

         w =  [tex]\frac{ I_1 w_1 + I_2 w_2 }{I}[/tex]            (1)

We already have the angular velocities of the system, let's find the kinetic energy of it

initial

          K₀ = K₁ + K₂ = ½ I₁ w₁² + ½ I₂ w₂²

final

          K_f = K = ½ I w²

the variation of the kinetic energy is the loss in the increase of the temperature of the system, they indicate us that we neglect the other possible losses

         ΔK = K_f -K₀

         ΔK = ½ I w² - (½ I₁ w₁² + ½ I₂ w₂²)           (2)

In this chaos we know all the values ​​for which the numerical value of ΔK can be calculated, the symbolic substitution gives expressions with complicated

Now if all this variation of energy turns into heat

         Q = ΔK

         m_{total} c_e ΔT = ΔK

where the specific heat of the bear discs must be known, suppose they are of the same material

         ΔT = [tex]\frac{\Delta K}{(m_1+m_2) c_e }[/tex]               (3)

to make a special case, we suppose some data

the discs have the same mass and radius, disc 2 is initially at rest and the discs are made of bronze that has c_e = 380 J / kg ºC

we look for the angular velocity

          I₁ = I₂ = I₀

          I = 2 I₀

we substitute in 1

           w = [tex]\frac{I_o w_1 + I_o 0 }{2I_o}[/tex] I₀ w₁ + I₀ 0 / 2Io

           w = w₁ /2

we look for the variation of the kinetic energy with 2

             ΔK = ½ (2I₀) (w₁ /2)² - (½ I₀ w₁² + ½ I₀ 0)

             ΔK = ¼ I₀ w₁² -½ I₀ w₁²

             ΔK = - ¼ I₀ w₁²

the negative sign indicates that the kinetic energy decreases

We look for the change in Temperature with the expression 3

              ΔT = [tex]\frac{ \Delta K}{(m_1 +m_2) c_e}[/tex]ΔK / (m1 + m2) ce

              ΔT = [tex]\frac{ \frac{1}{4} I_o w_1^2 }{ 2m c_e}[/tex]

              ΔT =  [tex]\frac{1}{8} \frac{ (\frac{1}{2} m r_1^2 ) w_1^2 }{ m c_e}[/tex]

              ΔT = [tex]\frac{1}{16} r_1^2 w_1^2 / c_e[/tex]

in this expression all the terms are contained

The increase in internal energy of the disks will be [tex]\rm \triangle E= mc\frac{\triangle k }{(m_1+m_2)c_e}[/tex].

The energy contained within a thermodynamic system is known as its internal energy. It's the amount of energy required to build or prepare a system in any given internal state.

The given data in the problem is;

[tex]\rm \omega_1[/tex]  is the angular velocity of  disk 1

[tex]\rm \omega_2[/tex] is the  angular velocity of disk 2

r₁ is the radius of  disk 1

r₂ is the radius of  disk 2

m₁ is the mass of disk 1

m₂ is the mass of disk 2

Momentum before the collision;

[tex]\rm L_1 = I_1 \omega_1[/tex]

The moment of inertia of disc 1

[tex]\rm i_1 = \frac{1}{2} m_1r_1^2[/tex]

The momentum gets conserved;

[tex]\rm L_0 = L_f \\\\ I_1 \omega_1 + I_2\omega_2 = I \omega \\\\ \rm \omega= \frac{I_1 \omega_1 + I_2\omega_2}{I}[/tex]

The change in the kinetic energy is;

[tex]\traingle KE= K_f - K_0 \\\\ \traingle KE= \frac{1}{2} I \omega^2-(\frac{1}{2} I_1\omega_1^2 + (\frac{1}{2} I_2\omega_2^2 )[/tex]

The change in the energy gets converted into heat;

[tex]\rm Q= \triangle k \\\\\ m_{total } c_e dt = \triangle k[/tex]

The change in the temperature is

[tex]\triangle T= \frac{\triangle k }{(m_1+m_2)c_e}[/tex]

The internal energy change is found by;

[tex]\rm \triangle E = mc_v dt[/tex]

[tex]\rm \triangle E= mc\frac{\triangle k }{(m_1+m_2)c_e}[/tex]

Hence the increase in internal energy of the disks will be [tex]\rm \triangle E= mc\frac{\triangle k }{(m_1+m_2)c_e}[/tex].

To learn more about the internal energy refer to the link;

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Answer:

(b) both the temperature and pressure of the gas decrease.

Explanation:

An ideal gas undergoes an adiabatic expansion, a process in which no heat flows into or out of the gas. As a result, both the temperature and pressure of the gas decrease.

Gay Lussac states that when the volume of an ideal gas is kept constant, the pressure of the gas is directly proportional to the absolute temperature of the gas.

Mathematically, Gay Lussac's law is given by;

[tex] PT = K[/tex]

Also, according to the first law of thermodynamics which states that energy cannot be created or destroyed but can only be transformed from one form to another. Thus, the ideal gas does work on the environment with respect to the volume and temperature.

Answer:

 t = 1.62 h

Explanation:

A flat mirror fulfills the law of reflection where the incident angle is equal to the reflected angle.

          θ_i = θ_r

If we use trigonometry to find the angles, the mirror is at a height of L = 1.87 m,   and the reflected rays reach a distance x1 = 3.56 m

         tan θ₁ = x₁ / L

         tan θ₁ = [tex]\frac{3.56}{1.87}[/tex]

         θ₁ = tan⁻¹  1.90

         θ₁ = 62.29º

for the second case x₂ = 1.46 m

        tan θ₂ = x₂ / L

        θ₂ = tan⁻¹  [tex]\frac{1.46}{1.87}[/tex]

        θ₂ = 37.98º

the difference in degree traveled is

         Δθ = θ₁- θ₂

          Δθ = 62.29 - 37.98

          Δθ = 24.31º

as in the exercise they indicate that every 15º there is an hour

         t = 24.31º (1h / 15º)

         t = 1.62 h

Answer:

in this case the weight of the vehicle does not change , consequently the friction force should not change

Explanation:

The friction force is a macroscopic manifestation of the interactions of the molecules between the two surfaces, this force in the case of solid is expressed by the relation

          fr = μ N

          W-N= 0

          N = W

as in this case the weight of the vehicle does not change nor does the Normal one, consequently the friction force should not change