Which scientist proposed the first atomic theory?

Explanation:

Coal is a fossil fuel and is the altered remains of prehistoric vegetation. The energy we get from coal today comes from the energy that plants absorbed from the sun millions of years ago. In the burning process of coal, carbon dioxide (CO2) is emitted. Humans expel CO2, and plants utilize it every single day. Carbon is a building block for all forms of life and is used in a lot of everyday products.

Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.Coal is formed when dead plant matter decays into peat and is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands—called coal forests—that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian) and Permian times. However, many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras.

Answer:

look it up of goog le

Explanation:

Answer:

The rate of change of distance is called speed it can also be defined as distance travelled per unit time,from these definition you can tell that the formula will be

speed=distance/time

in this question the distance is 900meters and the time is 55seconds therefore the speed will be:

s=900meters/55seconds

=16.36m/s

I hope this helps

Answer:

4 d

Explanation:

because the spring is balanced with t

Answer:

light reflects off the objects and enter our eyes

Answer:

Explanation:

[tex]a=\frac{v_f-v_0}{t}[/tex] We don't yet need the mass of the car, as we can see by this equation. What we do need is the velocity of the car, the initial velocity, in meters per second, and right now it's in km/hr. Not good. We need to convert. The conversion is as follows:

[tex]54\frac{km}{hr}*\frac{1000m}{1km}*\frac{1hr}{3600s}=15\frac{m}{s}[/tex] Ok, that's good. Now we have everything we need but the time element. If the car traveled a distance of 40 meters at 15 m/s, then we can use the d = rt equation to solve for t, and when we find t we plug it into the acceleration equation:

40 = 15t and

t = 2.7 seconds. The car traveled for 2.7 seconds to go that 40 meters. That's the only reason we were given the displacement. We need it for nothing else but that.

Filling in the acceleration equation now:

[tex]a=\frac{0-15}{2.7}=-5.6\frac{m}{s^2}[/tex] and the negative indicates we are in fact slowing down. That's the answer for the acceleration portion of the problem; now we need the force, F, applied to the brakes.

F = ma where m is mass (we get to use that value now!) and a is -5.6 m/s/s.

F = 500(-5.6) and

F = -2800 N and the negative here means that the force of the brakes is acting against the motion of the car: the brakes are pulling the car "backwards" to stop while the car's motion is forward. The negative indicates the direction the force is being applied.

Vtb xe máy là:

v=s : t= 500 : 25=20(m/s)

Answer:

203360Pa

Explanation:

Pressure= density of liquid*height*g

=1000*10*10

=100000Pa

Total pressure= water pressure + atmospheric pressure

=1000000+103360

=203360 Pascal

Answer:

he will be in profit

Explanation:

Himalayan region are high above the sea level so the gravity will be less there compared to the Terai region

Terai lies way below he Himalayan region so the pull of gravity will be more compared to Himalayan region

that's why he will be in profit but not loss

Explanation:

FALSE

The first periodic table of elements Mendeleev created contained 63 elements.

Answer:

The Planck constant, or Planck's constant, is a fundamental physical constant denoted h, and is of fundamental importance in quantum mechanics. A photon's energy is equal to its frequency multiplied by the Planck constant. Due to mass–energy equivalence, the Planck constant also relates mass to frequency.

Planck postulated that the energy of light is proportional to the frequency, and the constant that relates them is known as Planck's constant (h). His work led to Albert Einstein determining that light exists in discrete quanta of energy, or photons.

E = hf

[tex] \sf \: h = 6.626 \times {10}^{ - 34} \: kg \: {m}^{2} {s}^{ - 1} [/tex]

Answer:

a plumber

Explanation:

The temperature of a gas molecule is measured by the average translational kinetic energy

Answer:

The temperature of a gas is a measure of the average translational kinetic energy of the molecules. In a hot gas, the molecules move faster than in a cold gas; the mass remains the same, but the kinetic energy, and hence the temperature, is greater because of the increased velocity of the molecules

Explanation:

This is also from Go0gle because my explanation would've been an essay long .

but in shorter version if the gas molecules move fast it's hot an if it moves slow its cold hope this helps .

Answer:

250N

Explanation:

According to newton second law,

\sumF = ma

Fm - Ff = ma

Since the velocity is constant, a = 0m/s

Frictional force Ff = 250N

Substitute

Fm - 250 = m(0)

Fm - 250 = 0

Fm = 250N

Hence the force to keep the box sliding at constant speed is 250N

Answer:

I. Vs = 8.0 Volts.

II. Is = 4.5 Amperes.

Explanation:

Given the following data;

Np = 1.5Ns = [tex] \frac {N_{P}}{N_{S}} = 1.5 [/tex]  ..... equation 1

Ip = 3.0 A

Vp = 12 V

To find the voltage and current on the secondary coil;

I. For the voltage in the secondary coil (Vs), we would use the following formula;

[tex] \frac {V_{P}}{V_{S}} = \frac {N_{P}}{N_{S}} [/tex]  ...... equation 2.

Substituting eqn 1 into eqn 2, we have;

[tex] \frac {V_{P}}{V_{S}} = 1.5 [/tex]

[tex] \frac {12}{V_{S}} = 1.5 [/tex]

Cross-multiplying, we have;

[tex] V_{S} * 1.5 = 12 [/tex]

[tex] V_{S} = \frac {12}{1.5} [/tex]

Vs = 8.0 V

II. For the current in the secondary coil (Is), we would use the following formula;

[tex] \frac {I_{S}}{I_{P}} = \frac {N_{P}}{N_{S}} [/tex]  .... equation 3

Substituting eqn 1 into eqn 3, we have;

[tex] \frac {I_{S}}{I_{P}} = 1.5 [/tex]

[tex] \frac {I_{S}}{3.0} = 1.5 [/tex]

Cross-multiplying, we have;

[tex] I_{S} = 1.5 * 3.0 [/tex]

Is = 4.5 A

The shape is connected in parallel so;

5.1) Ans;

[tex] \frac{1}{R} = \frac{1}{R1} + \frac{1}{R2} \\ \frac{1}{R} = \frac{1}{2} + \frac{1}{3} \\ \frac{1}{R} = \frac{3 + 2}{6} = \frac{5}{6} \\ R = \frac{6}{5} = 1.2 \: \: ohm[/tex]

5.2) Ans;

[tex] \frac{1}{R} = \frac{1}{R1} + \frac{1}{R2} \\ \frac{1}{R} = \frac{1}{8} + \frac{1}{10} \\ \frac{1}{R} = \frac{5 + 4}{40} = \frac{9}{40} \\ R = \frac{40}{9} = 4.4 \: \: ohm[/tex]

I hope I helped you^_^

The distance, to the nearest tenth, is 314.9 light-years.

The given data is:

A recently discovered planet is located 1.85*10^5 miles from Earth.

Now we want to transform this distance to light-years.

Remember that a light-year is defined as "the distance that the light would travel in one year".

using the relation:

distance = speed*time

The speed of light is:

speed = 6.706*10^8 mi/h

And in one year has 8760 hours, then we have:

time = 8760 h

replacing these in the equation we get:

distance = speed*time

distance = (6.706*10^8 mi/h)*(8760 h)  = 5,874,456,000,000 miles

Son one light-year is equivalent to 5,874,456,000,000 miles

1 light-year = 5,874,456,000,000 miles

So to transform a distance in miles to light-years, we just need to divide that distance by 5,874,456,000,000 miles:

The distance between the new planet and Earth was:

D = 1.85*10^15 mi = ( 1.85*10^15)/(5,874,456,000,000) = 314.9 light-years.

if you want to learn more about this, you can read:

https://brainly.com/question/1302132

Answer:

The maximum current which can flow through a fuse without melting it, is called its rating. ... If current higher than 8 A flows through the fuse, it would melt and circuit gets broken. ... Hence, fuse acts as a safety device

Answer:

The guy above me is right

Explanation:

Explanation:

In scalar addition we have to do only the sum of magnitude as we know that the scalar quantities don't have direction.

since it is the scalar quantity the direction will be same for all the magnitudes.

Answer:

In scalar addition we have to do only the sum of magnitude as we know that the scalar quantities don't have direction...

since it is the scalar quantity the direction will be same for all the magnitudes.

on the other hand if it was a vector addition then it should be with two different directions which are considerable show the resultant vector needs to be calculated by vector addition method.

Answer:

F = 32.28 N

Explanation:

For this exercise we must use the rotational equilibrium relation

          Σ τ = 0

In the initial configuration it is in equilibrium, for which all the torque and forces are compensated. By the time the payment lands on the bar, we assume that the counter-clockwise turns are positive.

          W_bird  L / 2 - F_left 0.595 - F_right 0.595 = 0

we assume that the magnitude of the forces applied by the hands is the same

          F_left = F_right = F

          W_bird L / 2 - 2 F 0.595 = 0

          F = [tex]\frac{m_{bird} \ g L} { 4 \ 0.595}[/tex]

we calculate

         F = 0.560 9.8 14.0 /2.38

         F = 32.28 N

Answer:

A = 150 cm at 120 degc

Where A + B = C       find B

B = C - A          add -A to both sides

Ax = 150 cos 60 = -75

Ay = 150 sin 60 = 129.9

Likewise

Cx = 114.7

Cy = 80.3

Bx = Cx - Ax = 114.7 + 75 = 189.7

By = Cy - Ay = 80.3 -129.9 = -49.6

B = (189.7^2 + 49.6^2)^1/2 = 196.7       length of B vector

tan B = By / Bx = -49.6 / 189.7       B = -14.65 deg

Also

sin B = By / B = -49.6 / 196.1 = -14.65 deg

So B is 196.1 cm at -14.65 deg

Tenemos un problema de termodinamica sobre gases ideales, los cuales pueden ser descritos por la ecuación de estado del gas ideal

[tex]P*V = n*R*T[/tex]

donde:

P = presión

V = volumen

n = número de moles

R = constante de los gases

T = temperatura.

1) Para el primer problema podemos pensar que el gas dentro del globo es un gas ideal:

Originalmente sabemos que n = 4 y V = 5.0 L

Entonces tendremos:

[tex]P*(5.0 L) = (4 moles)*R*T[/tex]

Ahora decidimos agregar 8 moles más, dejando constante la presión y la temperatura, entonces podemos reescribir la ecuación de arriba como:

(5.0L)/(4 moles) = R*T/P

Y como R, T y P son constantes, entonces:

R*T/P es una constante.

Esto quiere decir que cuando agreguemos 8 moles, para tener un total de 12 moles, tendremos que:

V'/(12 moles) = R*T/P = (5.0L)/(4 moles)

Donde V' es el nuevo volumen final del globo, y es lo que queremos obtener.

V'/(12 moles) =  (5.0L)/(4 moles)

V' =   (5.0L)*(12 moles)/(4 moles) = (5.0 L)*3 = 15.0 L

2) Queremos obtener la densidad en gramos sobre litro de un gas con una masa molar de 60g/mol, a P = 0.75 atm y T = 25°C.

Primero pasemos la temperatura a grados kelvin:

T = 25°C = (25 + 273.15)°K = 298.15°K

Planteamos la ecuación del gas ideal:

[tex]P*V = n*R*T[/tex]

reemplazando R = 0.082 (atm*L/mol*k), además de la presión y la temperatura para un solo mol de gas:

[tex](0.75 atm)*V = (1 mol)*(0.082 (atm*L/mol*k))*(298.15°K)[/tex]

Resolviendo para V obtenemos que:

[tex]V = (1 mol)*(0.082 (atm*L/mol*k))*(298.15°K)/(0.75 atm) = 32.597 L[/tex]

Así, vemos que un mol de este gas ocupa un volumen de  32.597 L

Y también sabemos que un mol de este gas pesa 60 gramos.

Recordando que la densidad es el cociente entre la masa y el volumen, podemos ver que la densidad del gas será:

[tex]d = 60g/(32.597 L) = 1.84 g/L[/tex]

Si deseas leer mas sobre el tema, podes ver:

https://brainly.com/question/18528542

Total distance = 10 km + 10 km = 20 km

1 km = 1000 m

20km x 1000 = 20,000 m

Total time = 20 min. + 30 min. = 50 minutes

Average speed = Distance /  time

Average speed = 20,000/50 min

Average speed = 400 m/s

Answer:

Explanation:

Yes, According to law of conservation of energy, it has been said that energy cannot be created or destroyed.

Answer:

24J

Explanation:

The energy output will be the 20% it lost in efficiency:

120-80% = 24J

Answer:

Đáp án là vị trí để đặt q3 tại vị trí cân bằng là cách A một đoạn 0,0411 m

và nằm trong AB

Explanation:

Do q1 và q2 trái dấu nên q3 nằm trong

gọi r1 là vị trí từ A đến q3 suy ra r2=0.08-r1

Vị trí cân bằng nên [tex]\frac{q1}{r1^{2} }[/tex] = [tex]\frac{q2}{(0.08-r1)^{2} }[/tex]

Explanation:

st system:the internationak system of measurement which i declared form internationäl convention of scientists held in france in 1960AD is Si system

CGS System:it measure in length in centimeter mass in gram time in second

Answer:

nods 40th anniversary rid off e 49en9 snns

Answer:

301.6 N

Explanation:

The length of the wire L₀ = 8 m and its diameter, d = 4 mm = 4 × 10⁻³ m. Since its temperature drops by  10°C, it will have a change in length ΔL = L₀αΔθ where α = linear expansivity of steel, a 12 × 10⁻⁶ /K, and Δθ = temperature change = -10°C = -10 K(negative since it is a drop)

So, the strain, ε = ΔL/L₀ = αΔθ = 12 × 10⁻⁶ /K × 10 K = 12 × 10⁻⁵

Now the Young's modulus of steel, Y = σ/ε where σ = stress = T/A where T = increase in tension in steel wire and A = cross-sectional area of wire = πd²/4 where d = diameter of wire = 4 × 10⁻³ m and ε = strain = 12 × 10⁻⁵

So, σ = Yε

Since Y = 2 × 10¹¹ N/m².

Substituting the values of the variables into the equation, we have

σ = Yε

σ = 2 × 10¹¹ N/m² × 12 × 10⁻⁵

σ = 24 × 10⁶ N/m²

Since σ = T/A

T = σA

T = σπd²/4

Substituting the values of the variables into the equation, we have

T = σπd²/4

T = 24 × 10⁶ N/m² × π × (4 × 10⁻³ m)²/4

T = 24 × 10⁶ N/m² × π × 16 × 10⁻⁶ m²/4

T = 24 × 10⁶ N/m² × π × 4 × 10⁻⁶ m²

T = 96 N × π

T = 301.59 N

T ≅ 301.6 N

So, the increase in tension in the steel wire is 301.6 N

Answer:

Explanation:

The only one that doesn't have a time unit that is squared is the one that is a label for speed or velocity. Acceleration has a label with the time unit squared, like m/s/s. Choice D is the only unit for speed/velocity.

Answer: D

Explanation: metres per second (m/s)

Answer: There are multiple options:

By varying the supply voltage.

By varying the flux, and by varying the current through the field winding.

By varying the armature voltage, and by varying the armature resistance.

Helpful Link:

https://www.elprocus.com/what-are-the-best-ways-to-control-the-speed-of-dc-motor/