Describe or identify some uses of an electromagnet.

Answer:

It is most likely option A B and C

Answer:

I think option A ,B,D are correct

Answer:

Explanation:

I just did the Gizmo and the correct answer is 12 :) Hope this helps!

The total resistance of the circuit for parallel resistors of 41 Ω and 17 Ω is 12Ω. Hence option D is correct.

When two or more resistors are connected between two same points, they are said to be connected in parallel combination(as shown in fig).  The equivalent resistance is the reciprocal and the sum of reciprocals of all resistance connected in parallel combination.

[tex]\frac{1}{R_{s}} = \frac{1}{R_{1}} + \frac{1}{R_{2} } + \frac{1}{R_{3}} ..........+ \frac{1}{R_{n} }[/tex]  where Rs is the equivalent or total resistance of the circuit.

In parallel combination, same potential difference exists across each resistor. But current through each resistance is different.

When two or more resistors are connected one after other, they are said to be connected in series as shown in figure. in this combination voltage difference across each resistance is different which is given by ohms law. current flowing through each resistance is same.

equivalent resistance for series combination is given by,

R(s) = R₁ + R₂ + R₃...........+R(n).

In this problem given resistance are not seen, Resistor can be with 41 and 17Ω.

Given,

R₁ = 17 Ω

R₂ = 41 Ω

[tex]R_{s} = ?[/tex]

by parallel combination,

[tex]\frac{1}{R_{s}} = \frac{1}{R_{1} } + \frac{1}{R_{2} }[/tex]

[tex]R_{s} = \frac{R_{1} R_{2} }{R_{1} + R_{2} }= \frac{17*41}{17+41} = \frac{697}{58} = 12[/tex]

R = 12 Ω.

Hence option D is correct.

To know more about Resistor :

https://brainly.com/question/24297401

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Answer:

10.1 m/s

Explanation:

Let the coordinates of the pelican's position be (x, y).

Now, since it is dropped from a height of 12.3 m, then initial velocity is zero and using Newton's 2nd law of motion, we have;

12.3 = 0 - ½gt²

½gt² = 12.3

t² = 12.3 × 2/9.8

t² = 2.51

t = √2.51

t = 1.5843 s

Now, it travels 16.0m horizontally before it hits the water below. Using the formula, distance = speed × time, we have;

16 = v_x•t

Thus;

16 = v_x × 1.5843

v_x = 16/1.5843

v_x = 10.1 m/s

Now, the velocity in the vertical y-direction is zero.

Thus;

v = √((v_x)² + (v_y)²)

v = √((10.1² + 0²))

v = 10.1 m/s

Answer:I think it’s convection

Explanation:

Answer:

ok so first ur not a failure and its okay don't be so hard on ur self

Electrons move from the wool to the rod.

BEcause if they move from wool to rod, the rod has more number of electrons now. Hence making it negatively charged

The plastic rod becomes charged when electrons move from the wool to the rod to become negatively charged. Details about charge can be found below.

Electronegativity is the tendency, or a measure of the ability, of an atom or molecule to attract electrons and thus form bonds.

According to this question, a plastic rod becomes negatively charged when it is rubbed with a piece of wool.

An atom becomes negatively charged when it gains electrons from another atom, hence, it can be said that the plastic rod becomes charged when electrons move from the wool to the rod to become negatively charged.

Learn more about charge at: https://brainly.com/question/19886264

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Answer:

Nuclear power plants are fueled by uranium, which emits radioactive substances. Most of these substances are trapped in uranium fuel pellets or in sealed metal fuel rods. However, small amounts of these radioactive substances (mostly gases) become mixed with the water that is used to cool the reactor.

Answer:

Part A

The sound intensity at the location 150 from the firework = 4.3[tex]\overline 5[/tex] W/m²

Part B

The power the firework is emitting is approximately 1,231.5 kW

Explanation:

Part A

The data of the firework sound heard by the two friends are;

Let 'A' represent the location of the friend at a point 150 m from the fireworks and let 'B' represent the location of the friend watching from a distance of 700 m from the firework

The distance of 'A' from the sound, r₁ = 150 m

The distance of 'B' from the sound, r₂ = 700 m

The intensity at which 'B' hears the sound, I₂ = 0.2 W/m²

The relationship between sound intensity and distance is given as follows;

[tex]\dfrac{I_2}{I_1} = \left (\dfrac{r_1}{r_2} \right )^2[/tex]

[tex]\therefore {I_1} = \dfrac{I_2}{ \left (\dfrac{r_1}{r_2} \right )^2} = I_2 \times \left (\dfrac{r_2}{r_1} \right )^2[/tex]

Plugging in the values gives;

[tex]\therefore {I_1} = 0.2 \times \left (\dfrac{700}{150} \right )^2 = \dfrac{196}{45} = 4.3\overline 5[/tex]

The sound intensity at location 'A', I₁ = 4.3[tex]\overline 5[/tex] W/m²

Part B

The relationship between power, 'P', and intensity, 'I', is presented as follows;

[tex]I = \dfrac{P}{4 \cdot \pi \cdot r^2}[/tex]

P = I·4·π·r² = 4·I·π·r²

Therefore, at point 'A', where the distance, r₁ = 150 m, and the intensity, I₁ = 4.3[tex]\overline 5[/tex] W/m², we have;

P = 4 × 4.3[tex]\overline 5[/tex] W/m² × π × (150 m)² = 1231504.32021 W

The power the firework is emitting, P ≈ 1,231.5 kW.

the difference of 10 dB is considered as having 10 times the intensity, so difference of 40 dB means :

=》10 × 10 × 10 × 10

=》10000 times

so the the intensity of one sound is 10000 times the other one.

Answer:

Amplitude—distance between the resting position and the maximum displacement of the wave

Frequency—number of waves passing by a specific point per second

Period—time it takes for one wave cycle to complete

wavelength λ - the distance between adjacent identical parts of a wave, parallel to the direction of propagation.

Tension - described as the pulling force transmitted axially by the means of a string, a cable, chain, or similar one-dimensional continuous object, or by each end of a rod, truss member, or similar three-dimensional object

Answer:

the anser is B

Explanation:

Answer:

=> Rheostat is an electric device used as a variable resistance, like the regulator of the fan. It is used to change the electric resistance in the electric circuit.

=> Rheostat works on the principle of Ohm’s law. Ohm’s law states that current in a circuit is inversely proportional to the resistance at the given temperature.

[tex] \infty \infty \infty [/tex]

Answer:

That is because we apply less Work.

Brainliest?? I hope this helps!!!

Explanation:

Explanation:

Momentum of an object is defined as the product of the mass of object and the velocity with which it is moving.

p = mv

where, p = momentum, m= mass and v= velocity

mass m = 0.7 Kg and v = 20 m/s

p = 0.7×20 = 14 Kg-m/sec

Therefore, momentum of the object  = 14 kg-m

Answer:

(a) h = 1.5 m (b) v = 5.29 m/s

Explanation:

1. Given that,

Mass of a rollercoaster cart, m = 4500 kg

It has 67,500 J of gravitational potential  energy.

We know that, the gravitational potential  energy is given by :

[tex]E=mgh[/tex]

Put all the values,

[tex]h=\dfrac{E}{mg}\\\\h=\dfrac{67500}{4500\times 10}\\\\h=1.5\ m[/tex]

2. The kinetic energy of an object is given by :

[tex]E=\dfrac{1}{2}mv^2\\\\v=\sqrt{\dfrac{2E}{m}}\\\\v=\sqrt{\dfrac{2\times 63000}{4500}}\\\\v=5.29\ m/s[/tex]

Hence, this is the required solution.

Answer:

FALSE

Explanation:

You breath in oxygen and your blood takes it through your body then you breath it out as carbon dioxide

Answer: When a liquid substance is poured into a vessel, it takes the shape of the vessel, and, as long as the substance stays in the liquid state, it will remain inside the vessel. Furthermore, when a liquid is poured from one vessel to another, it retains its volume (as long as there is no vaporization or change in temperature) but not its shape.

Explanation: A solid has a definite shape and volume. A liquid has a definite volume, but takes the shape of its container. A gas lacks either a defined shape or volume. Plasma is similar to a gas in that its particles are very far apart, but a gas is electrically neutral and plasma has a charge.

Answer:

B

Explanation:

Liquid

Answer:

1/2 m u^2     initial Kinetic Energy of body

m g h        Potential Energy body attains as it rises to height

1/2 m u^2 = m g h      conversion of KE to PE

h = u^2 / ( 2  g)

Answer:

north pole of a magnet repels the north pole of another magnet no matter of their shape , size , weakness , strength ,etc .

Explanation:

Answer:

Height of tower = 480 meter

Explanation:

Given:

Initial velocity = 20 m/s

Time taken to reach ground = 8 second

So,

Final velocity = 0 m/s

Acceleration due to gravity = 10 m/s²

Find:

Height of tower

Computation:

s = ut + (1/2)(g)(t)²

s = (20)(8) + (1/2)(10)(8)²

s = 160 + (1/2)(10)(64)

s = 160 + (10)(32)

s = 160 + 320

s = 480 meter

Height of tower = 480 meter

Answer: A. at the point which

is twice the focal lenght of the lens of the camera

Explanation:

When a certain document is to be produced through the use of a duplicating camera, it should be noted that the camera should be placed at the point which is twice the focal lenght of the lens of the camera so as to get the exact copy of the document.

It should be noted that placing the camera between the principal and a point twice the focal lens of the camera lens or beyond a point that's twice the focal length will not produce the document.

Therefore, the correct option is A

Answer:

C

Explanation:

Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces

I hope this helps a little bit

The correct Option is :

=》(C) The square of the distance that separates them

where,

f = gravitational force

r = distance between the objects

Answer:

[tex]L=11.3\ kg-m^2/s[/tex]

Explanation:

Given that,

Angular speed of a skater, [tex]\omega=3\ rot/s=18.84\ rad/s[/tex]

The moment of inertia of the skater, I = 0.6 kg-m²

We need to find the angular momentum of the skater. The formula for the angular momentum of the skater is given by :

[tex]L=I\omega[/tex]

Substitute all the values,

[tex]L=0.6\times 18.84\\\\L=11.3\ kg-m^2/s[/tex]

So, its angular momentum is equal to [tex]11.3\ kg-m^2/s[/tex].

Answer:

I can't see option dear

Explanation:

Answer:

infinity

Explanation:

this is because time is irrelevant

Answer: Hello Results of examples 5.4 and 5.5 are missing from your question but I was able to find it online and use it to resolve your question

answer :

a) 1780 m^3/sec

b)  23.81 m

Explanation:

a) calculate the number of m^3 of water flowing through an OTEC plant charge

assumption : assuming an ideal heat engine

 Q / t   =  m*c*∆T * (eff) / t

1e^9 J/s = 1g/cc *V(1cal/g°C) * 2°C (6.7%)*(4.184J/cal) / t

Hence:  V / t ( number of m^3 of water ) = 1.78e^9 cc / sec = 1.78 * 10

= 1780 m^3/sec

b) Determine the diameter of pipes

Given that the water flows at  4m/s  ( velocity )

1780 m^3 /sec = A * V  ------ ( 1 )

A = π*d^2/4 =  1780 / 4 = 445 m^2  -------- ( 2 )

v = 4 m/s

Back to equation 2

d^2 = ( 445 * 4 ) / π

      ≈ 567

∴ necessary diameter ( d ) = [tex]\sqrt{567}[/tex] = 23.81 m

Answer:

Sunlight allows plants to perform photosynthesis, a process which is required for plant growth and health. ... Plants that are denied sufficient light will eventually lose their color and die. Plants deprived of light will grow upward, stretching their stems more rapidly that usual, searching for light.

Answer:

Sunlight allows plants to perform photosynthesis, a process which is required for plant growth and health. ... Plants that are denied sufficient light will eventually lose their color and die. Plants deprived of light will grow upward, stretching their stems more rapidly that usual, searching for light

Explanation:

i got this from  

https://sciencing.com/what-happens-to-plants-if-they-have-no-sun-12486997.html#:~:text=Sunlight%20allows%20plants%20to%20perform,for%20plant%20growth%20and%20health.&text=Plants%20that%20are%20denied%20sufficient,that%20usual%2C%20searching%20for%20light.

Answer:

[tex]g=2.513m/s^2[/tex]

Explanation:

From the question we are told that:

Mass Taken [tex]m=100g \approx 100*10^{-3}[/tex]

Strain on Spring [tex]l_s=22.6cm \approx 22.6*10^{2}[/tex]

Distance pulled down [tex]d_d=10.9[/tex]

Time for ten oscillations take [tex]t=18.8s[/tex]

Generally the equation for angular velocity is mathematically given by

[tex]\omega=2\pi\\\omega=2\pi*\frac{10\ oscillations}{t}\\\\\omega=2\pif=2\pi*\frac{10\ oscillations}{18.8}\\Also\\\omega=\sqrt{\frac{k}{m}} \\\omega=\sqrt{\frac{k}{100*10^{-3}}}[/tex]

Therefore

[tex]{2\pi*\frac{10\ oscillations}{18.8}}=\sqrt{\frac{k}{100*10^{-3}}} \\k=\sqrt{2\pi*\frac{10\ oscillations}{18.8}}*100*10^{-3}\\k=1.112N/m[/tex]  

Generally the equation for Acceleration due to gravity is mathematically given by

[tex]F=mg\\mg=k l_s\\g=\frac{k l_s}{m}\\g=\frac{1.112*2.6*10^{2}}{100*10^{-3}}[/tex]

[tex]g=2.513m/s^2[/tex]