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3 years ago

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Find the approximate kinetic energy of a circular wheel of radius r and mass M that is rotating about its center at 2 cycles/s.

Assume the wheel’s mass is concentrated at the rim and the mass of the wheel’s spokes is negligible.

1 answer:

alukav5142 [94]3 years ago

6 0

Answer:

$8M(r\pi)^2$

Explanation:

First we convert 2 cycles/s to angular velocity knowing that each circle has an angle of 2π

$\omega = 2 * 2\pi = 4\pi rad/s$

Then we calculate the moment of inertia of the cylindrical shell, assuming there's no mass inside the wheel (only at the rim):

$I = mr^2 = Mr^2$

So the kinetic energy of this is

$E_k = I\omega^2/2 = Mr^2*(4\pi)^2/2 = 8M(r\pi)^2$

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A 50 mm diameter steel shaft and a 100 mm long steel cylindrical bushing with an outer diameter of 70 mm have been incorrectly s

BARSIC [14]

Answer:

The axial force is $P = 15.93 k N$

Explanation:

From the question we are told that

The diameter of the shaft steel is $d = 50mm$

The length of the cylindrical bushing $L =100mm$

The outer diameter of the cylindrical bushing is $D = 70 \ mm$

The diametral interference is $\delta _d = 0.005 mm$

The coefficient of friction is $\mu = 0.2$

The Young modulus of steel is $207 *10^{3} MPa (N/mm^2)$

The diametral interference is mathematically represented as

$\delta_d = \frac{2 *d * P_B * D^2}{E (D^2 -d^2)}$

Where $P_B$ is the pressure (stress) on the two object held together

So making $P_B$ the subject

$P_B = \frac{\delta _d E (D^2 - d^2)}{2 * d* D^2}$

Substituting values

$P_B = \frac{(0.005) (207 *10^{3} ) * (70^2 - 50^2))}{2 * (50) (70) ^2 }$

$P_B = 5.069 MPa$

Now he axial force required is

$P = \mu * P_B * A$

Where A is the area which is mathematically evaluated as

$\pi d l$

So $P = \mu P_B \pi d l$

Substituting values

$P = 0.2 * 5.069 * 3.142 * 50 * 100$

$P = 15.93 k N$

8 0

3 years ago

The bandgap of InP semiconductor laser is 1.0 eV. The effective mass of the valence band is ½ of the effective mass of the condu

klemol [59]

Answer: the wavelength of this transition is 1.2039 um

Explanation:

Given that;

the energy level between the transitioning energy gap Eg = 1.0 + 0.03 = 1.03 eV

we know that λ = 1.24 / Eg

so we substitute our Eg into the above equation

λ = 1.24 / 1.03

λ = 1.2039 um

therefore the wavelength of this transition is 1.2039 um

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2 years ago

Describe the general characteristics of the nearest stars. (Size, luminosity, color, etc., do not include specific stars)

Darina [25.2K]

Answer: The five general characteristics of the nearest stars are the brightness, color, surface temperature, size, and mass.

Explanation:

The mass of a star can be described as being measured with our sun at 1 solar mass. One star can equal the size of our sun. There is one star named, Rigel, that is bigger than the Earths sun. Each star will vary in its density.

The size of the star, as stated above, can be the size of our sun and sometimes larger. The size is measured by solar radii.

Stars vary in their temp. They range anywhere from -273.15 degrees Celsius to 50,000 K. The temp is based on the Kelvin scale.

The stars brightness are always based on luminosity and magnitude.

The stars colors will vary and is based on the temperature of the surface of the star. Some stars are red in color, white in color, and some even have a bluish color.

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3 years ago

Need help ASAP!!!! here are the options: Amplitude, Compression, Rarefaction, and Wavelength

Strike441 [17]

Amplitude is the pair of vertical buttons, so to speak. Compressions are the bunched up vertical lines with the purple arrows pointing left and right. Rarefactions are purple arrows pointing down. Wavelength is crest to crest purple buttons. Associated LH and RH pointing arrows.

6 0

2 years ago

A farmer using sustainable agriculrural practices will a. use increased crop diversity and fewer off the farm resources in order

kati45 [8]

a. use increased crop diversity and fewer off the farm resources in order to reduce pressure on resources

Explanation:

A farmer using sustainable agricultural practices will use increased crop diversity and fewer off the farm resources in order to reduce dependency on other resources.

The major goal of sustainable agriculture is to cultivate plants and groom livestock in the best way that won't alter the environment.

This usually entail the cultivation of different crops.
Diversity of crops provides the means to sustain and retain soil fertility naturally without having to add fertilizers.
In animal husbandry, some of wastes are used on farm and the excesses from the farm are used to feed livestock.
Sustainable agriculture is a practice of self-reliant agriculture without infringing on the environment.

learn more:

Human impact on rainforest brainly.com/question/12095428

#learnwithBrainly

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3 years ago