Who discovered natural magnet for the first time?​

Answers

Answer 1
Answer: Magnes



Explanation: Magnes found that the nails and buckle of his sandals and the tip of his staff were attracted to the rock he was standing on. He dug up the Earth to find lodestones. Lodestones contain magnetite, a natural magnetic material Fe3O4.

Related Questions

Which device uses electricity to produce a rotational motion? A computer C magnet B generator D motor​

Answers

Answer:

B generator

Explanation:

why are dams have broader walls at the bottom?

Answers

A dam has broader walls at the bottom than at the top to withstand the great pressure of water which increases with increase in depth.

Which statement best describes the relationship between an object's density and its index of refraction?

A. As the mass per unit volume of the substance increases, the refractive index decreases.

B. As the mass of the object increases, the refractive index decreases.

C. As the physical density of the substance increases, the refractive index increases

D. As the optical density increases, the refractive index increases​

Answers

Answer:

D. As the optical density increases, the refractive index increases

Answer: the answer is D

Explanation: I took the test

NEED HELP A string is fixed at both ends and standing waves with 5 loops are produced. If the length of the string is 60 cm, what is the wavelength of the waves?Single choice.
(2 Points)

6 cm

12 cm

18 cm

24 cm

Answers

Answer:

12 cm is the required answer for your question

hope it is helpful to you

Answer: 12

Explanation:

60/5=12

why transparent object don't form a shadow​

Answers

Explanation:

Transparent objects do not form shadows. The light passes completely from the transparent objects thus these objects will not form shadow. ... In such objects, the light gets refracted thus, such objects forms shadow. The refraction is also the reason why we can see such objects.

Explanation:

cause it pass the light coming from the source of light

A 2800 kg truck moving at 12 m/s to the right hits a stopped 1100 kg car. What is the combined velocity the moment they stick together?

Answers

Answer:

The combined velocity is 8.61 m/s.

Explanation:

Given that,

The mass of a truck, m = 2800 kg

Initial speed of truck, u = 12 m/s

The mass of a car, m' = 1100 kg

Initial speed of the car, u' = 0

We need to find the combined velocity the moment they stick together. Let it is V. Using the conservation of momentum.

[tex]m_1v_1+m_2v_2=(m_1+m_2)V\\\\V=\dfrac{m_1v_1+m_2v_2}{(m_1+m_2)}\\\\V=\dfrac{2800\times 12+0}{2800+1100}\\\\V=8.61\ m/s[/tex]

So, the combined velocity is 8.61 m/s.

Q
16) A student pushes four students on skateboards. She pushes as hard as she can each time. She measures how far each student
goes before stopping. Which is most likely to happen?
A) The biggest student will go the furthest.
B) The smallest student will go the furthest.
c) Each student will go further than the last.
D) All four student will go about the same distance.

Answers

Answer:

B

Explanation:

It would be diffrent if on a downward slope but assuming your going straight it would be the smallest student.

The smallest student will go furthest if all the students push with the same amount of force. Therefore, option (B) is correct.

What is Newton's second law of motion?

According to Newton’s second law of motion, the force equals the mass of the body times the acceleration of that body when the body has constant mass.

This law states that the acceleration of a body depends on two variables. The first one is the mass of the body and the force acting on the body. The acceleration of a body is directly proportional to the net force acting on the body and inversely proportional to the mass.

Newton’s second law can be expressed in the equation as shown below:

[tex]F= ma[/tex]

or,

[tex]a=\frac{F}{m}[/tex]

Acceleration or gaining speed of a body happens when a force acts on it.

When all four students are pushed by the same amount of force then the acceleration of the smallest student will be greatest as the mass of the smallest student will be least.

Therefore, the smallest student will go furthest in comparison to all other students.

Learn more about Newton's second law of motion, here:

brainly.com/question/13447525

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If you are 1 m above the surface of the earth, and then you jump to 2 m above the surface of the earth.
The force of gravity between you and the earth will be:
a.) About 4
b.) About 12
c.) About the same

Answers

Answer:

b

Explanation:

Which of the following
statements is correct?
A. Matter flows one way, but energy cycles in an
ecosystem.
B. Matter cycles in an ecosystem, but energy
flows into, and eventually exits, an ecosystem.
C. Matter and energy can flow and cycle in an
ecosystem, depending on the temperature,
D. Neither matter nor energy cycle in an
ecosystem

Answers

The correct statement is B. Matter cycles in an ecosystem, but energy flows into, and eventually exits, an ecosystem.

What is ecosystem?

Ecosystem is a community of living organisms interacting with each other and their physical environment. It includes plants, animals, microorganisms, soil, water, and other resources, and the chemical and energy exchanges between them.

This is because energy enters an ecosystem through sunlight and is transformed through the process of photosynthesis by producers, like plants, into chemical energy. This energy is then passed on to consumers, like humans, through a food chain. Eventually, energy exits the ecosystem in the form of heat, which is released into the environment. On the other hand, matter cycles within an ecosystem through a process called the biogeochemical cycle. Nutrients, like carbon and nitrogen, enter the environment from different sources and are taken up by producers and then passed on to consumers. The matter is then returned to the environment as waste, which is then taken up by producers again.

To know more about biogeochemical cycle,

https://brainly.com/question/1204069

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Which wave has the lowest amplitude?

Answers

Wave D has the lowest amplitude. The highest point of a wave is called amplitude.

What is amplitude?

The distance between from the crest of a wave to the next crest is known as the amplitude. It is denoted by a.

The standard equation for the SHM is found as;

[tex]\rm y = asin \omega t[/tex]

Where, a represent the amplitude of the wave.

In the wave D it is observed that the distance from center axis to the highest point of the wave is smallest. Hence, wave D has the lowest amplitude.

To learn more about the amplitude, refer to the link;

https://brainly.com/question/8662436

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Answer:

To summarize what the expert answer said, it's the last box.

Explanation:

A pressure of 7x10^5N/m is applied to all surfaces of a copper cube (of sides 25 cm) what is the fractional change in volume of a cube? ( for copper B= 14x10^10N/m)

Answers

Answer:

The correct solution is "[tex]5\times 10^{-4}[/tex] %".

Explanation:

The given values are:

Pressure,

[tex]\Delta P=7\times 10^5 \ N/m[/tex]

for copper,

[tex]B=14\times 10^{10} \ N/m[/tex]

As we know,

The Bulk Modulus (B) = [tex]\frac{\Delta P}{-\frac{\Delta V}{V} }[/tex]

or,

The decrease in volume will be:

= [tex](\frac{\Delta V}{V})\times 100 \ percent[/tex]

then,

= [tex]\frac{\Delta P}{B}\times 100 \ percent[/tex]

On putting the values, we get

= [tex]\frac{7\times 10^5}{14\times 10^{10}}\times 100 \ percent[/tex]

= [tex]5\times 10^{-4} \ percent[/tex]

What would make oppositely charged objects attract each other more? increasing the positive charge of the positively charged object and increasing the negative charge of the negatively charged object decreasing the positive charge of the positively charged object and decreasing the negative charge of the negatively charged object increasing the distance between the positively charged object and the negatively charged object maintaining the distance between the positively charged object and the negatively charged object

Answers

Answer:

A.

Explanation:

I did the test :D

which feature is used to classify galaxies
age
color
shape
size

Answers

Answer:Shape

I took the quiz

Answer:shape

Explanation:

I took the quiz

How are wave properties and energy related?
give me examples

Answers

Answer:

They don’t ‘represent’ anything, they are properties of the wave.

Depending on the type of wave, we experience them as various phenomena. For example, with a sound wave we experience frequency (or wavelength, which is just another way to describe the same property) as the pitch of the sound. We experience amplitude as the loudness of the sound, although due to the characteristics of the ear, frequency also effects perceived loudness.

If the wave is a light wave, we experience the frequency (wavelength) as the colour of the light, and the amplitude as the brightness of the light.

For many waves, we don’t perceive them at all (e.g. radio waves).

For ocean waves, frequency is the time for each peak or trough to reach us, and amplitude is how tall the wave is.

Pravat exerts a force of 30 N to lift a bag of groceries 0.5 m. How much work did Pravat do on the bag?

Answers

Answer:

15 J

Explanation:

Work = Force x Distance

15= 30 x 0.5

Have a blessed day!

Answer:Pravat did 15 J of work

Explanation:

NEED HELP The main difference between kinetic energy and potential energy is thatSingle choice.
(2 Points)

kinetic energy involves position, and potential energy involves motion.

kinetic energy involves motion, and potential energy involves position.

although both energies involve motion, only kinetic energy involves position.

although both energies involve position, only potential energy involves motion.

Answers

Answer:

kinetic energy involves motion, and potential energy involves position.

although both energies involve position, only potential energy involves motion.

hope it is helpful to you ☺️☺️✌️

Kinetic energy is motions and potential energy is stored up energy

If a book has a weight of 23.3 N on earth, what is its mass

Answers

Answer:

2.38 kg

Explanation:

by definition, weight in physics is the force of gravity (Fg)

Fg = mass x gravity or mg

gravity is 9.8 m/s^2

N = kg m/s^2

Fg = mg

23.3 kg m/s^2 = 9.8 m/s^2 x m

23.3 kg m/s^2 / 9.8 m/s^2 = m    >>> m/s^2 cancel out

23.3/9.8 = 2.37755 kg

m = 2.38 kg

Please help me ; - ;
Match the food choice with its potential long-term result.
1. eating a piece of cake with 8 grams of fat
2. eating an egg salad sandwich on whole grain bread with 9 grams of fat
3. eating a cheeseburger with 48 grams of fat

A. heart disease
B. obesity
C. weight loss

Answers

Answer:

2 = C

3 = B

1 = A

Explanation:

Help meeee help plsssss

Answers

Answer:

3a. 240 C

3b. 3666.67 A

Explanation:

3a. Determination of the charge.

Current (I) = 2 A

Time (t) = 120 s

Charge (Q) =?

The charge, current and time are related by the following equation:

Charge (Q) = current (I) × time (t)

Q = It

With the above formula, we can obtain the charge as follow:

Current (I) = 2 A

Time (t) = 120 s

Charge (Q) =?

Q = It

Q = 2 × 120

Q = 240 C

Thus, the charge is 240 C

3b. Determination of the current

We'll begin by converting 220 KC to C. This can be obtained as follow:

1 KC = 1000 C

Therefore,

220 KC = 220 KC × 1000 C / 1 KC

220 KC = 220000 C

Next, we shall express 1 minute in second. This is shown below:

1 min = 60 s

Finally, we shall determine the current. This can be obtained as follow:

Charge (Q) = 220000 C

Time (t) = 60 s

Current (I) =?

Q = It

220000 = I × 60

Divide both side by 60

I = 220000 / 60

I = 3666.67 A

Thus, the current flowing through the bulb is 3666.67 A

Two parallel plates have an area of
0.00100 m^2. How much charge
must you place on them to create a
1000 N/C field between the plates?
(The answer is *10^-12 C. Just fill
in the number, not the power.)

Answers

Answer:

8.85

Explanation:

The computation of the charge that must place on them in order to create 1000 N/C field between the plates is shown below:

We know that

E = (Q/A) ÷ E_o

1000 = Q ÷ 0.01×8.85× 10^-12

Q = 8.85 × 10^-12

So,

The answer is 8.85

The above formula should be applied so that the correct value could come

And, the same would be relevant

Answer:

8.85

Explanation:

acellus

An astronaut lands on an alien planet. He places a pendulum (L = 0.200 m) on the surface and sets it in simple harmonic motion, as shown in this graph.

(a) What is the period and frequency of the pendulum’s motion?
(b) How many seconds out of phase with the displacements shown would graphs of the velocity and acceleration be?
(c) What is the acceleration due to gravity on the surface of the planet in? Determine the number of g-forces.
Show any necessary calculations.

Answers

I think b or c sorry

Tom used 75 N of force to push a box 3 meters across the floor. How much work did he do?
0.12 J
25 J
1
78J
225 J

Answers

Answer:

It must be 225 J.

Explanation:

According to

Work done = Force × distance travelled

                    =  75      × 3

                    = 225 J

This answer is taken so since no angles are stated in the question.

The density of silver is 10.49 g/cm3. If a sample of pure silver has a volume of 12.993 cm3, what is the mass?

Answers

Explanation:

Density=mass/volume

mass=x

10.49=X/12.99

X=10.49 X12.99

X=136.29657

mass=136.3g/cm^3

I hope it helped.

what are the two
factors in which weight of object depends?​

Answers

Answer:

An object's weight depends on its mass (the amount of matter it consists of) and the strength of the gravitational pull.

Two factors that affect the weight of an object is mass and constant gravitational force.

What is the electrical power when the current is 20 amps and the voltage is 15 volts? *


A. 1.33 watts

B. 300 watts

C. 35 watts


Objects in space appear to change position as they orbit the sun. What is this phenomenon called? *


A. Nebular theory

B. Stellar theory

C. Parallax


The moon lacks an atmosphere because its gravity is too STRONG and forces gas molecules into outer space. *


A. True

B. False


Heat pumps move heat from __________ to __________ areas & REQUIRES energy.

A. cold, hot

B. hot, cold

Answers

Answer:

The power is 300 watts.

Explanation:

Given that,

Current, I = 20 a

Voltage, V = 15 volts

The electrical power of any device is given by the product of current and voltage. It can be given by :

P = VI

So,

P = 15 × 20

= 300 W

So, the power is 300 watts.

URGENT HELP PLS

1. Given a force-displacement curve as shown in the figure, what does the area of the region enclosed by the curve represent?

A. The force acting on the object

B. The displacement of the object

C. The magnitude of the coefficient of static friction

D. The work done on the object by the force

Answers

Explanation:

work done is equals to force into displacement in the direction of force

Ans: D

Un automóvil se mueve 80 m en 40 s con una velocidad constante. ¿Cuál es la velocidad del automóvil? Ayuda plissssssssssssssssssssss

Answers

Answer:

Velocidad = 2 m/s

Explanation:

Dados los siguientes datos;

Distancia = 80 m

Tiempo = 40 s

Para encontrar la velocidad del automóvil;

La velocidad se puede definir como la tasa de cambio en el desplazamiento (distancia) con el tiempo.

La velocidad es una cantidad vectorial y, como tal, tiene magnitud y dirección.

Matemáticamente, la velocidad viene dada por la ecuación;

[tex] Velocidad = \frac {distancia} {tiempo} [/tex]

Sustituyendo en la fórmula, tenemos;

Velocidad = 80/40

Velocidad = 2 m/s

A crane lifts a load of 15000N to a height 40m in 50 seconds. Calculate the power of the crane​

Answers

Answer:

P = 12000 W

Explanation:

General data:

F = 15000 N d = 40 mt = 50 sP = ?

Work is force times unit of distance. So in order to calculate the power we must first calculate the work.

Formula:

[tex]\boxed{\bold{W=\frac{F}{d}}}[/tex]

Replace and solve

[tex]\boxed{\bold{W=\frac{15000\ N}{40\ m}}}[/tex][tex]\boxed{\bold{W=600000\ J}}[/tex]

once the work is found, we proceed to find the power according to the formula:

[tex]\boxed{\bold{P=\frac{W}{t}}}[/tex][tex]\boxed{\bold{P=\frac{600000\ J}{50\ s}}}[/tex][tex]\boxed{\boxed{\bold{P=12000\ W}}}[/tex]

The power of the crane is 12000 Watts.

Greetings.

Read the text again

Answers

i think it is 1.F2.T3.T4.F5.T

Why is the EM important?

Answers

Answer:

It is important because it furnishes information about the composition, the temperature and maybe the mass or relative velocity of the body that emits or absorbs it.

Explanation:

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