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3 years ago

What is the energy of a photon of this light, in ev ?

Physics

1 answer:

Stels [109]3 years ago

7 0

U7g19xuih;8weoxhwe8ou1whuowxhw

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What is menat by the age of the universe? how old is the universe?

ikadub [295]

The universe is 13.8 billion years old.

7 0

3 years ago

Read 2 more answers

A car travels 82 meters do North and 14 seconds the car turns around and travels 44 m due south in four seconds what is the magn

Yakvenalex [24]

Answer:

2.11 m/s

Explanation:

Take north to be positive and south to be negative.

Average velocity = displacement / time

v = (82 m + -44 m) / (14 s + 4 s)

v = 2.11 m/s

The velocity is positive, so it is 2.11 m/s north. The magnitude of the velocity is 2.11 m/s.

8 0

3 years ago

What is the force per unit area at this point acting normal to the surface with unit nor- Side View √√ mal vector n = (1/ 2)ex +

Mumz [18]

Complete Question:

Given $\sigma = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right]$ at a point. What is the force per unit area at this point acting normal to the surface with $\b n = (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z$ ? Are there any shear stresses acting on this surface?

Answer:

Force per unit area, $\sigma_n = 28 MPa$

There are shear stresses acting on the surface since $\tau \neq 0$

Explanation:

$\sigma = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right]$

equation of the normal, $\b n = (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z$

$\b n = \left[\begin{array}{ccc}\frac{1}{\sqrt{2} }\\0\\\frac{1}{\sqrt{2} }\end{array}\right]$

Traction vector on n, $T_n = \sigma \b n$

$T_n = \left[\begin{array}{ccc}10&12&13\\12&11&15\\13&15&20\end{array}\right] \left[\begin{array}{ccc}\frac{1}{\sqrt{2} }\\0\\\frac{1}{\sqrt{2} }\end{array}\right]$

$T_n = \left[\begin{array}{ccc}\frac{23}{\sqrt{2} }\\0\\\frac{27}{\sqrt{33} }\end{array}\right]$

$T_n = \frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z$

To get the Force per unit area acting normal to the surface, find the dot product of the traction vector and the normal.

$\sigma_n = T_n . \b n$

$\sigma \b n = (\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z) . ((1/ \sqrt{2} ) \b e_x + 0 \b e_y +(1/ \sqrt{2}) \b e_z)\\\\\sigma \b n = 28 MPa$

If the shear stress, $\tau$ , is calculated and it is not equal to zero, this means there are shear stresses.

$\tau = T_n - \sigma_n \b n$

$\tau = [\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z] - 28( (1/ \sqrt{2} ) \b e_x + (1/ \sqrt{2}) \b e_z)\\\\\tau = [\frac{23}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{33}{\sqrt{2} } \b e_z] - [ (28/ \sqrt{2} ) \b e_x + (28/ \sqrt{2}) \b e_z]\\\\\tau = \frac{-5}{\sqrt{2} } \b e_x + \frac{27}{\sqrt{2} } \b e_y + \frac{5}{\sqrt{2} } \b e_z$

$\tau = \sqrt{(-5/\sqrt{2})^2 + (27/\sqrt{2})^2 + (5/\sqrt{2})^2} \\\\ \tau = 19.74 MPa$

Since $\tau \neq 0$ , there are shear stresses acting on the surface.

3 0

2 years ago

Which statement correctly defines displacement

Andreyy89

Displacement is B) the shortest distance between the starting point and the ending point of a motion

Explanation:

Displacement is a vector quantity; it is a vector connecting the initial position to the final position of motion of an object.

Since it is a vector, it has both a magnitude and a direction:

The magnitude of the displacement is the length of the vector, therefore it corresponds to the shortest distance in a straight line between the starting point and the ending point of the motion
The direction goes from the starting point to the ending point

Therefore, the correct answer is

B) the shortest distance between the starting point and the ending point of a motion

Note that displacement is very different from distance. Consider for example an object moving in a circle, returning to its initial position: in this case, the distance covered by the object is not zero (it is the length of the circle), however the displacement is zero, because the initial position corresponds to the ending position.

Learn more about distance and displacement:

brainly.com/question/3969582

#LearnwithBrainly

6 0

2 years ago

Classify the following elements as alkine, alkine-earth, or transition metals based on their position on the periodic table

azamat

Explanation:

Iron transition metal

Potassium Alkaline metal

Strontium Alkaline earth metal

Platinum transition metal

The periodic table arranges elements based on their atomic numbers into periods and groups. Atomic number is the number of protons an atom contains.

On the periodic table:

Group IA is called Alkaline metal

Group IIA is the Alkaline earth metals

Group IIIA Boron family elements

Group VIIA Halogens

Group O Noble gases or inert gases.

Group IIIB to IIB Transition elements.

Running a check of the given elements on the periodic table will confirm answer.

Learn more:

Periodic table brainly.com/question/8543126

#learnwithBrainly

7 0

2 years ago