The key insight that Bohr introduced to his model of the atom was that the angular momentum of the electron orbiting the nucleus was quantized. He introduced the postulate that the angular momentum could only come in quantities of nh/(2π), where h is Planck's constant and n is a nonnegative integer (0,1,2,3,…). Given this postulate, what are the allowable values for the velocity v of the electron in the Bohr atom? Recall that, in circular motion, angular momentum is given by the formula L= mvr.

Answer:

Ming treasure voyages

Explanation:

Answer:

i think the answer is 32 something

Explanation:

Answer:

What is the difference between a geostationary satellite and a non-geostationary satellite? Geostationary (GSO) satellites occupy an orbital position 36,000 km above the earth, and remain in a stationary position relative to the Earth itself.

The maximum compression in the spring is 0.06883 meters.

Given to us,

mass of bullet, [tex]m= 16.2\ grams[/tex]

velocity of bullet, [tex]v= 850\ meter/second[/tex]

mass of the block, [tex]m_2= 40\ kilograms[/tex]

velocity of block, [tex]v_2= 0\ meter/second[/tex]

spring constant, [tex]k = 1000\ Newton/meter[/tex]

Combined mass after collision,

[tex]\begin{aligned}M&= m_1+m_2\\&= 40.0162\ Kilograms\end{aligned}[/tex]

Using the momentum conservation equation, to find out final velocity of the system(bullet and block combined)

[tex]m_1v_1+m_2v_2= MV\\[/tex]

[tex]0.0162\times 850+40\times 0 = 40.0162\times V\\V= 0.3441 meter/sec[/tex]

Now using the Conservation of Energy (Kinetic energy of the system will be equal to potential energy in the spring), to find out the displacement of the spring [tex](x)[/tex]

[tex]\frac{1}{2}kx^2 = \frac{1}{2}MV^2\\\\\frac{1}{2}\times 1000\times x^2= \frac{1}{2} \times40.0162\times0.3441^2\\\\x^2= 0.004738\\\\x= 0.06883\ meters[/tex]

Hence, the maximum compression in the spring is 0.06883 meters.

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Answer:

The correct answer is "53.15 days".

Explanation:

Given that:

Half life of [tex]131_{I}[/tex],

[tex]T_{\frac{1}{2} }= 8 \ days[/tex]

To find t when R will be "1%" of [tex]R_o[/tex], then

⇒ [tex]R=\frac{1}{100}R_o[/tex]

As we know,

⇒ [tex]R=R_o e^{-\lambda t}[/tex]

or,

∴ [tex]e^{\lambda t}=\frac{R_o}{R}[/tex]

By putting the values, we get

        [tex]=\frac{R_o}{\frac{R}{100} }[/tex]

        [tex]=100[/tex]

We know that,

Decay constant, [tex]\lambda = \frac{ln2}{T_{\frac{1}{2} }}[/tex]

hence,

⇒ [tex]\lambda t=ln100[/tex]

     [tex]t=\frac{ln100}{\lambda}[/tex]

        [tex]=\frac{ln100}{\frac{ln2}{8} }[/tex]

        [tex]=53.15 \ days[/tex]  

Answer:

The rope is stretched by 0.3373 cm

Explanation:

As we know  

Youngs Modulus ([tex]5.0 * 10^9[/tex] N/m2) is Stress divided by strain

Stress = force/Area = (65*9.8)/(pi * (7.3*10^-3)^2)

Starin = change in length/original length of the rope = l/12 meters

Substituting the given values we get  

[tex]5.0 * 10^9[/tex] N/m2 = {([tex]\frac{\frac{24*9.8}{\pi *(7.3*10^{-3})^2} }{\frac{\delta L}{L} }[/tex])

[tex]5.0 * 10^9[/tex] N/m2 = {([tex]\frac{\frac{24*9.8}{\pi *(7.3*10^{-3})^2} }{\frac{\delta L}{12} }[/tex])

[tex]\frac{\delta L}{12} = \frac{\frac{65*9.8}{pi * (7.3*10^-3)^2} }{5.0 * 10^9}[/tex]

The rope is stretched by 0.3373 cm

Answer:

c and b

Explanation:

hope this helped!

Answer:

the ball lose kentic energy and gains potential energy rolling upward

Answer:

c

Explanation:

when a ball is rolling down it loses potential and gains kinetic, but in this case since the ball is going upwards it is losing kinetic energy and gaining potentail like a roller coaser

Answer:

A tsunami is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water.

Answer:

A tsunami is series of waves caused by heavy winds. Hurricanes can cause tsunami

Explanation:

Answer:

Hi how are you doing today Jasmine

Answer:

The answer is B

Explanation:

I did the USA test prep

Answer:

At a personal level, barriers to critical thinking can arise through: ... self-centred or societal/cultural-centred thinking (conformism, dogma and peer-pressure) unconscious bias, or selective perception. an inability to be receptive to an idea or point of view that differs from your own (close-mindedness)

Explanation:

Answer:

a)  3.265 kg-m^2

b)  - 4.96  rad/s^2

c) 16.1944 N-m

d) 35.625

e)  - 1.488 m/s^2

f)  67.1175 m.

Explanation:

Given data:

Diameter of grindstone ( D ) = 0.650 m ,  Radius ( R ) = 0.325 m

mass of grindstone ( M ) = 55 kg

Radius of shaft ( r ) = 0.300 m

mass of shaft ( m ) = 4 kg

Initial Angular velocity = 450 rev/min = f = 7.5 rev/s = w  =15π rad/s

time ( t ) = 9.50 secs

a) Determine the moment of inertia of the grindstone including the shaft

moment of inertia of grindstone = MR^2 / 2 = 55* (0.325)^2 / 2 = 2.905

moment of inertia of shaft = mr^2 = 4 *0.3^2 = 0.36

∴ moment of inertia including shaft = 2.905 + 0.36 = 3.265 kg-m^2

b) Determine the angular acceleration of the grindstone

∝ = - 15π / 9.5 ( i.e.  angular velocity / time )

   = - 4.96  rad/s^2 ( deceleration value )

c) Determine average torque done by friction to bring the grindstone to rest

Torque ( I * ∝ )  = 3.265 x 4.96 = 16.1944 N-m (magnitude)

d) Determine the number of revolutions before grindstone comes to rest

Total revolutions N before grindstone comes to rest

= ( f1 + f2)* t /2 = 7.5 * 9.5 / 2 = 35.625

Note : f2 = 0 as it comes to rest

          f1 = 7.5 rev/s

e) Determine the Linear acceleration of the shaft in this process

This can be calculated using this relation

r * ∝ = 0.3 x (- 4.96 ) = - 1.488 m/s^2

f) Determine the linear distance travelled by the shaft

This can be calculated with the relation below

r * 2 * π * N = 0.3 * 2π * 35.625 = 67.1175 m.

Answer:

The fifth harmonic frequency is 2.9 KHz.

Explanation:

For a closed tube, the fifth harmonic frequency is also the second overtone. So that;

fifth harmonic frequency = [tex]\frac{5V}{4L}[/tex]

where V is the velocity of the sound in air, and L is the length of the tube.

But L = 0.15 m and V = 343 m/s, then:

fifth harmonic frequency = [tex]\frac{5*343}{4*0.15}[/tex]

                                     = [tex]\frac{1715}{0.6}[/tex]

                                     = 2858.33 Hertz

fifth harmonic frequency = 2.9 KHz

The fifth harmonic frequency of the soda bottle is approximately 2.9 KHz.

Answer:

2828.33

Explanation:

answer for acellus

Answer:

parallel circuit is a kind of circuits in which all components are connected between the same two sets of electrically common points, creating multiple paths for the current to flow from one end of the battery to the other:

Answer:

Gadhe hote hai log and usme sabse pehele aati hai Jonain jaise log waah waah xD

Brainliest krdena warna chappal padenge -,-

Answer:

The object has decreasing acceleration and decreasing velocity.

Answer:

it's very easy and simple answer u can't do it

The electric field intensity at a point of 15cm from a charge of 10 μc will be 3.9 ×10⁶ N/C.

The electric field is defined as the area over an electric charge where its impact may be felt. The force experienced by a unit positive charge deposited at a given position is known as the electric field intensity.

The formula for the electric field intensity is given as;

[tex]\rm E= \frac{q}{4 \pi \epsilon d^2 } \\\\ \rm E= \frac{10 \times 10^{-6}}{4 \times 3.14 \times 8.85 \times 10^{-12}(15 \times 10^{-2}^2 } \\\\ E=3.9 \times 10^6 \ NC^{-1}[/tex]

Hence the electric field intensity at a point of 15cm from a charge of 10 μc will be 3.9 ×10⁶ N/C.

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Answer:

A.

Explanation:

A po sa tingin ko

sana po makatulong

Explanation:

hope it's helpful

have a nice day!!!! ;)

Answer:

Onel de guzman now he's 44,the first world's computer virus has admitted to his guilt.

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Answer:

Explanation:

Question 1 (1 point)

According to theory, which term best describes the universe before the big bang?

a small densely packed ball of matter

Question 2 (1 point)

Which example is used as evidence that the universe began with the big bang?

Question 2 options:

leftover energy in the form of background radiation in the universe from the event

Question 3 (1 point)

How do scientists use the Doppler effect to understand the universe?

to determine motion of objects

Question 4 (1 point)

The Doppler effect indicates that the universe is expanding because_________.

Which phrase best completes the sentence.

light from other galaxies is red shifted

Question 5 (1 point)

What does a blue shift in light from stars indicate?

The stars are moving closer.

Sorry I don't know the answer

Stopping a 1000 kg car moving at a speed of 174 km/h will be more difficult than stopping an identical car moving at 100 km/h.

This can be explained by using Newton's second law of motion which says that the rate of change of momentum of a body is equal to the force applied.

Therefore, the car moving at 174 km/h has higher momentum and from Newton's second law of motion, a higher force would be required to stop this car.

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Answer:

Explanation:

An orbit is a regular, repeating path that one object in space takes around another one, it's an imaginary path of the Earth around the Sun.

Answer:

the lens you must select has an angle of 143º measured with respect to the horizontal, this angle is 53º with respect to the vertical.

Explanation:

The glare is caused by the reflection of light in the water, the polarization of the reflected light is polarized in a direction parallel to the surface of the water, the polarization is total for the angles

         n = tan  [tex]\theta_{p}[/tex]

         \theta_{p} = tan⁻¹ n

the refractive index for seawater is 1.33

         \theta_{p}= tan⁻¹  1.33

         \theta_{p} = 53º

for this angle the light is totally polarized, for the other angles the polarization is partial.

Based on this, the lenses must eliminate this polarization, so its polarization direction must have 90º with respect to this polarization,

          \theta_{lens} = 53 +90

           \theta_{lens}= 143º

Therefore, the lens you must select has an angle of 143º measured with respect to the horizontal, this angle is 53º with respect to the vertical.

A lens that could work is one that is polarized 45º with respect to the vertical.

The glass that is worn to eliminate glare must be able to remove glare away from the user.

The term sunglasses refers to the kind of glasses that are worn to prevent glare from the sun. This is because the glasses are made of polaroid materials that eliminate glare.

The question is incomplete as the sunglasses are not shown. However, the glass that is worn to eliminate glare must be able to remove glare away from the user.

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Answer:

Im so so sorry but I do now know how to do this

Explanation:

Answer:

[tex]X=165 \textdegree[/tex]

Explanation:

From the question we are told that:

Wavelength [tex]\lambda =360m[/tex]

Angle [tex]\theta=90 \textdegree[/tex]

Distance variation [tex]d=130m[/tex]

Generally the equation for phase difference X is mathematically given by

 [tex]X=\theta+\frac{d}{\lambda}*100[/tex]

 [tex]X=90+\frac{150}{360}*100[/tex]

 [tex]X=165 \textdegree[/tex]

Therefore Phase difference X is given as

 [tex]X=165 \textdegree[/tex]

Answer:

in case they lose control going downhill.

Explanation:

which is why they usually have a steep incline and are quite long. You see them used typically when the trucks brakes fail.

Answer:

The theory of evolution by natural selection, first formulated in Darwin's book "On the Origin of Species" in 1859, is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits