ai là người phát hiện trái đất hình cầu đầu tiên ?

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Answer 1

Answer:

Can't understand the language


Related Questions

Grain is pouring into a silo to be stored for later use. Due to the friction between pieces of grain as they rub against each other during the pouring process, one piece of grain picks up a charge of 6.0 E -10 C and another piece of grain picks up a charge of 2.3 E -15 C. What is the electric force between them if the pieces of grain are 2 cm apart?

Remember to identify all data (givens and unknowns), list equations used, show all your work, and include units and the proper number of significant digits to receive full credit.

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Answer:

3.1×10⁻¹¹ N is

Explanation:

is the answer

Can you solve this question?

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Hi there!

In this instance, the object's centripetal force is provided by the horizontal component of the tension, so:

Tsinθ = mv²/r

**We use sine because in this situation, the angle is with the vertical**

We can plug in the known values for tension and theta:

60sin(60) = mv²/r

51.96 = mv²/r

The radius is equivalent to the sine of the string in respect to theta:

sin(60) = O/H = r/L

2sin(60) = 1.732 m

Now, solve for the velocity:

51.96 = mv²/r

51.96r / m = v²

51.96(1.732)/.400 = v²

v² = 225

v = 15 m/s

Why is acceleration of an object moving at a constant velocity always zero?

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Answer:

If an object is moving with a constant velocity, then by definition it has zero acceleration. So there is no net force acting on the object. The total work done on the object is thus 0 (that's not to say that there isn't work done by individual forces on the object, but the sum is 0 ).

Explanation:

In the middle, when the object was changing position at a constant velocity, the acceleration was 0. This is because the object is no longer changing its velocity and is moving at a constant rate.

The mass of fifteen washers is _____ kg, which exerts a force of _____ N

Answers

Answer:

It could be related with the lesson from which this question belongs as far we did not read the lesson

Sorry

The more matter in an object, the _____.(1 point)


lower its weight and mass

lower its weight and mass


more likely it is to have gravity

more likely it is to have gravity


greater its gravitational attraction to Earth

greater its gravitational attraction to Earth


less likely it is to have weight on the moon

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Answer:

more likely it is to have gravity

You are in Paris, 50. m up on an Eiffel Tower support leg observation deck. If you throw a euro downward at a velocity of -1.0 m/s, how long would it take the coin to hit the ground?​

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Here’s my work to your question. I used kinematic equations to solve. :)

You illuminate the surface of some metal with green laser and observe the photocurrent. If you decrease the intensity of laser, the stopping potential will

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Remain the same.

Explanation:

The kinetic energy of the ejected electrons, and thus the resulting photocurrent, does not depend on the intensity of the incident radiation. Instead, it depends on the frequency. So since the stopping potential is used to reduce the photocurrent to zero and the photocurrent does not depend on the intensity, the stopping potential remains the same.

which one would cool down faster, water or a block of concrete? why?

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Answer:

If you mean by temperature

Water, cause say the water just sits there, it'll take a few minutes to cool down. But for concrete having all the hot sun rays on it during summer, can make it very hot, if you put 'cold water' there, it'll only last there for a moments (and that's by effect not waiting), if you wait for it to cooldown by itself, it'll take quite awhile.

If you mean solidify:

The stuff required to make concretes takes HOURS and HOURS to finish solidifying, unlike water being turn into ice normally only takes about half an hour or an hour (maybe 2) in the freezer (I don't know how long for ice, but not long at all in comparison to concrete).

Explanation:

Explanation was mostly part of the answer

Four balls with different masses are dropped from the heights shown. Air resistance may be ignored. Which ball has the greatest average speed?

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Answer:

The one falling from the greatest height will have the greatest speed.

h = 1/2 g t^2        time for ball to fall distance h

h2 / h1 = t2^2 / t1^2       dividing equations

h2 / t2^2 = h1 / t1^2

Let v be the average speed (v2 = h2 / t2)

1 / t2 * v2 = 1 / t1 * v1

v2 / v1 = t2 / t1      the one taking the longest to fall has the greater av. speed

Check:

h4 / h1 = t4^2 / t1^2     or

t4 / t1 = (h4 / h1)^1/2

In this case t4 / t1 = (4 / 1)^1/2 = 2  or twice the average speed

t1 = (2 h / g)^1/2 = .2^1/2 = .447       using g = 10

t4 = (2 h / g)^1/2 = .8^1/2 = .894

v1 = 1 / .447 = 2.24 m/s average speed

v4 = 4 / .894 = 4.47    or twice the average speed

7. What is the velocity of an object with a distance of 90m south and a time of
5s?

Answers

Answer:

Explanation:

v= s/t

V =90m/5s

V = 8m/s

Which of these is Newton's 3rd law of motion?

Equal and opposite forces

F = m x a

Inertia

Gravity

Answers

the answer is equal and opposite forces.

If you apply a net force of 100 N to the hoverboard, and it accelerates
2m/s/s, how much mass does it have?

Answers

Answer:

50 kg

Explanation:

The mass of an object given only the force acting on it and it's acceleration can be found by using the formula

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

f is the force in N

a is the acceleration in m/s²

From the question

f = 100 N

a = 2 m/s²

We have

[tex]m = \frac{100}{2} = 50 \\ [/tex]

We have the final answer as

50 kg

Hope this helps you

a heat engine is a device that uses to produce useful work

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A heat engine is a device that uses to produce useful work.

Definition - a device for producing motive power from heat, such as a gasoline engine or steam engine.

So..

If this is a true or false question.. Your answer is:

TRUE

Answer:

HEAT

Explanation:

The energy transfer diagram for a piece of equipment is shown. You are using a hand-cranked flashlight. One minute of cranking typically provides about 30 to 60 minutes of light.
Describe ALL of the energy transformations that are taking place in this process.
A) mechanical energy to heat energy Eliminate
B) electrical energy to light energy
C) mechanical energy to light energy
D) chemical energy to mechanical energy
E) mechanical energy to electrical energy

Answers

Answer:

n/a

Explanation:

No diagram found. I am willing to help

In a hand-cranked flashlight first, mechanical energy produced with the hand is converted into electrical energy then the electrical energy is converted into light energy, therefore the correct answers are the option B and option E.

What is mechanical energy?

The sum of all the energy in motion (total kinetic energy) and all the energy that is stored in the system (total potential energy) is known as mechanical energy.

The expression for total mechanical energy can be given as follows

ME= PE + KE

As given in the problem, the energy transfer diagram for a piece of equipment is shown. You are using a hand-cranked flashlight. One minute of cranking typically provides about 30 to 60 minutes of light.

The transformation that is taking place is the mechanical energy to electrical energy and then electrical energy to light energy.

Thus, the correct options are option are B and E.

Learn more about mechanical energy from here, refer to the link;

brainly.com/question/12319302

#SPJ2

the distance between two charges q a and q b is r and the force between them is F. What is the force between them if the distance between them is doubled?

Answers

The force will be reduced to 1/4 of the original

Explanation:

According to Coulomb's law, the force between two charges [tex]q_a\:\text{and}\:q_b,[/tex] separated by a distance r is given by

[tex]F = k\dfrac{q_aq_b}{r^2}[/tex]

where k is the Coulomb constant.

Now let F' be the force between the two charges when their separation distance is doubled. We can write this force as

[tex]F' = k\dfrac{q_aq_b}{(2r)^2} = k\dfrac{q_aq_b}{4r^2}[/tex]

[tex]\;\;\;\;\;= \frac{1}{4}\left(k\dfrac{q_aq_b}{r^2}\right) = \frac{1}{4}F[/tex]

Therefore, the force will be reduced to a quarter of its original value.

Hope you could understand.

If you have any query, feel free to ask.

What is the amplitude of this wave ?

Answers

Amplitude of a wave is the maximum displacement of the particles of a medium from their mean positions during the propagation of a wave.Here, the maximum displacement of the particles during wave propagation is equal to the height of the crests, i.e., EN or the depth of the troughs, i.e., MC.So, EN and MC are the amplitudes of the wave.The measure of EN is 1 mm.Hence, the amplitude of the wave is 1 mm.Note : I haven't considered -1 mm because amplitude cannot be negative.

Hope you could get an idea from here.

Doubt clarification - use comment section.

Important parts of stydi g physics

Answers

Answer:

put your question in proper way' i hope you understand.

Explanation:

Which is true of gamma radiation? O A. It increases the number of protons. O B. It is the heaviest of the three types. O C. It does not cause transmutation. O D. It has a positive charge.

Answers

Answer:  Your answer Is A)

Explanation:    

Its direction of deflection shows it possitively charged

It brings one element into another by bombardment(transmutation)

"A soccer ball is kicked horizontally off a 22 m high hill and lands a distance of 35 m from the edge of the hill." Which variable is 35 m? *

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Answer:Let’s assume that, after the soccer ball is kicked and moves through its trajectory, it first makes contact with level ground a horizontal distance of 35 meters from where it was kicked. Let’s also assume that we can neglect air resistance. The time, t, that the soccer ball is in the air until it first contacts the ground can be found from the equation h = (1/2)gt^2 which can be rewritten as t = sqrt(2h/g) where h is the vertical distance the ball falls which is the height of the hill since the ball was kicked horizontally, and g is the acceleration of gravity which is 9.8 m/s^2. So t = sqrt(2(22)/9.8) = 2.12 seconds. In that time, the ball travelled 35 meters so its horizontal velocity was 35 meters/2.12 seconds = 16.5 meters/second.

Explanation:

How much energy does a 150 N child have sitting on a 35M high cliff

Answers

Answer:

150+35=185 Plsss Brainliest plssss

Would you please help me with this? I can't figure it out, please! I need to know what the E means!

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Answer:

Without the full content of your question, I will have to GUESS at the context and assume

E = Energy

released when glucose is broken down.

Which feature of a balanced chemical equation demonstrates the law of
conservation of mass?
O A. It has the same types of atoms on both sides of the reaction
arrow.
O B. It shows the reactants of a chemical reaction to the left of the
reaction arrow.
O C. It has coefficients to show how much of each substance a
chemical reaction uses.
Thing
D. It shows the products of a chemical reaction to the right of the
reaction arrow.

Answers

Answer:  A) It has the same types of atoms on both sides of the reaction

arrow.

Explanation:  A balanced equation demonstrates the conservation of mass by having the same number of each type of atom on both sides of the arrow.

2 difference between calorimetry and calorimeter ​

Answers

Calorimetry :

the process of measuring the amount of heat released or absorbed during a chemical reaction.

Calorimeter :

device for measuring the heat developed during a mechanical, electrical, or chemical reaction, and for calculating the heat capacity of materials.

Which is an electromagnetic wave A. The waves that heat a cup of water in a microwave oven B. A flag waving in the wind C. Turning on a flashlight D.The changes in the air that result from blowing a horn

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Answer:

The answer would be A. The waves that heat a cup of water in a microwave oven

The density of water is 1000 kg/m the pressure pf water at 10 m depth is about

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Answer:

pressure in liquids is given as:

P= hpg

where h is the depth

where p is the density

where g is 10

Explanation:

From the formula above

p = 10 X 1000 X 10

p = 100000N/m

25 gram saturated solution of potassium nitrate at 95 C is cooled down to 55 C then how much gram of crystals of potassium nitrate will be separated if the solubility of potassium nitrate at 95 c is 100 and 55 C is 25 correspondingly ​

Answers

The mass of  potassium nitrate (KNO₃) crystals that will be separated is calculated as 6.25 g.

The given parameters:

Mass of KNO₃ = 25 gInitial temperature = 95 ⁰CFinal temperature = 55 ⁰CSolubility at 95 ⁰C = 100 MSolubility at 55 ⁰C = 25 M

The mass of KNO₃ at 95 ⁰C is calculated as follows;

[tex]m = \frac{25\ g \times 100\ g}{100\ g} \\\\m = 25 \ g[/tex]

mass of water = 100 g - 25 g = 75 g

The mass of KNO₃ at 55 ⁰C is calculated as follows;

[tex]m = \frac{75 \ g \times 25 \ g}{100 \ g} \\\\m = 18.75 \ g[/tex]

The mass of  potassium nitrate (KNO₃) crystals that will be separated is calculated as;

[tex]m= 25\ g \ - \ 18.75 \ g\\\\m = 6.25 \ g[/tex]

Thus, the mass of  potassium nitrate (KNO₃) crystals that will be separated is calculated as 6.25 g.

Learn more about saturated solution and temperature here: https://brainly.com/question/4529762

An automobile moving along a straight track changes its velocity from 40 m/s to 80 m/s in a distance of 200 m. What is the (constant) acceleration of the vehicle during this time

Answers

Answer:

[tex]\huge\boxed{\sf a = 1200\ m/s\²}[/tex]

Explanation:

Given Data:

Initial Velocity = Vi = 40 m/s

Final Velocity = Vf = 80 m/s

Distance = S = 200 m

Required:

Acceleration = a = ?

Formula:

2aS = Vf² - Vi² (THIRD EQUATION OF MOTION)

Solution:

2a (200) = (80)² - (40)²

400a = 6400 - 1600

400a = 4800

Divide 400 to both sides

a = 4800 / 400

a = 1200 m/s²

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

~AH1807

half-life questionnnnn:

Answers

120 and 150 and 180 and 210

22 Newton force is working on a 1,901 gram object. What is the acceleration in
meter/s^2 unit

Answers

Answer:

11.573

Explanation:

f = m*a

where f is the force in Newtons, m is the mass of the object (in kg) and a is the acceleration

so, we solve for a

a = f/m

a = 22/1.901

a = 11.573

The force shown in the figure(Figure 1) moves an object from x = 0 to x = 0.75 m.
1/How much work is done by the force?
2/How much work is done by the force if the object moves from x = 0.20 m to x = 0.55 m ?

Answers

Answer:

(a) The force changes its magnitude with respect to displacement, hence the total work will be sum of increment of work in three steps:-

step 1 . from 0 to 0.25m .

force = 0.6 N

displacement= 0.25m

work done =( force × displacement) = (0.25 × 0.6 ) = 0.15 joule.

step 2:- .

work done in moving from 0.25 to 0.50 m.

work done = ( force × displacement) = ( 0.4 × 0.25) = 0.10 Joule. .

step 3 :-

work done in moving from 0.50 to 0.75 m

work done = 0.8 × 0.25 = 0.200 joule.

hence total work done = ( 0.20+0.10+0.15) = 0.45 joule. ans

(b) similar concept you have to use here also.

step 1:

from 0.20 to 0.50, force of magnitude 0.4 N acts on the object.

Work done = ( 0.50-0.20)× 0.4 = 0.30 × 0.4 = 0.12 joule.

step :- 2

from 0.50 to 0.55 , force of magnitude 0.8 N acts on the block.

work done = 0.8× ( 0.55- 0.50) = 0.04 joule

total work done = 0.04 + 0.12 = 0.16 joule. ans

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