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Monica [59]
2 years ago
8

A Web site that ends in .gov or .edu is probably unreliable. True False

Physics
2 answers:
Aleonysh [2.5K]2 years ago
8 0

Answer:

false, they are more reliable.

Explanation:

i had to do it last year.

Mars2501 [29]2 years ago
4 0

Answer: Yes

Explanation: It is probably a trust worthy website

You might be interested in
Why do you think the speed of sound is higher<br> in solids, than liquids and gases?
mr Goodwill [35]

Answer:

Explanation:

Particles of a solid are closely packed, and  when a solid is hit to produce a sound the kinetic energy present in the solid will cause the particles to vibrate vigorously in the intermolecular spaces in the solid, whereas the paticles of liquids and gases are rather further apart therefore having large intermolecular spaces between particles.

8 0
3 years ago
A ball is thrown downward with an initial velocity of 12.1 m/s. How long will it take to reach a velocity of -24.5 m/s? (Negativ
xxMikexx [17]

Answer:

Explanation:

The sig figs are off in the answer (unless you use -9.81 for the acceleration due to gravity. My classes always use -9.8, which is 2 sig figs. But nevertheless, we can solve it!) Use the velocity formula:

v_f=v_0+at where vf is the final velocity, v0 is the initial velocity, a is the acceleration due to gravity, and t is the time in seconds. Filling in, using the fact that both the velocities are negative since the ball is going down:

-24.5 = -12.1 +(-9.8)t or

-24.5 = -12.1 - 9.8t and

-12.4 = -9.8t and divide to get that

t = 1.27 sec

5 0
3 years ago
Which of the following sets of properties leads to a high degree of thermal shock resistance? (A) High fracture strength High th
Rina8888 [55]

Answer:  

The correct Answer is C) <u>High fracture strength,</u> <u>High Thermal Conductivity,</u> <u>Low modulus of elasticity,</u> <u>Low coefficient of thermal</u>                                                                                                                                                                                                                                              

Explanation:

The ability of a solid to withstand sudden changes in temperature either during heating or cooling is known or referred to as Thermal Shock Resistance (TSR).

Thermal shock resistance is one of the most crucial factors of performance in solids for high temperature environments that can cause thermal stresses and risks for thermal shock damage.

Examples are as of such environments are energy conversion systems, electronic devices and cutting tools.

A common way to evaluate TSR is to look for maximum jump in surface temperature which a material can sustain without cracking.  This is known as thermal conductivity.

Failure due to thermal shock can be prevented by;

  • Reducing the thermal gradient seen by the object, by changing its temperature more slowly or increasing the material's thermal conductivity
  • Reducing the material's coefficient of thermal expansion
  • upping its strength
  • Introducing built-in compressive stress, as for example in tempered glass and in some cases tempered plastic
  • reducing its Young's modulus
  • increasing its toughness, by crack tip blunting (i.e., plasticity or phase transformation) or crack deflection

Thermal conductivity is an intensive physical property of a material that relates the heat flow through the material per unit area to temperature gradient across the material. The thermal conductivity of a material is basically a measure of its ability to conduct heat.    

The other factor that contributes to a high degree of thermal shock is:

Fracture Strength: This is the ability of a material containing a crack to resist fracture or resist becoming brittle. For example, glass has a high strength, but the presence of a small fracture reduces the strength. Therefore, glass has low fracture resistance. Fracture toughness is an important consideration in hydraulic fracture design.

Modulus of Elasticity:

An object or substance's resistance to being deformed elastically (i.e., non-permanently) when a stress is applied to it is calculated  or measured by a quantity known as Elastic Modulus (also known as Young modulus of elasticity)

A stiff material has a high Young's modulus and changes its shape only slightly under elastic loads (e.g. steel or diamond). A flexible material has a low Young's modulus and changes its shape considerably (e.g. rubbers).

Coefficient of thermal expansion (CTE) this refers to how the rate of change in the  size of an object with respect of every degree change in temperature assuming that pressure remains the same. An object with low CTE is Fine Ceramics or Advanced Ceramics.

Cheers!

               

4 0
2 years ago
You are training a classification model with logistic regression.
aalyn [17]

Answer:

B) Adding many new features to the model makes it more likely to over fit the training set.

Explanation:

Increasing number of features without increasing the amount of training data, increase over fitting in the model because features may be irrelevant and increase the redundant information in the model.

5 0
3 years ago
Read 2 more answers
Are the divisions of the electromagnetic spectrum distinct? Explain your answer
yKpoI14uk [10]

Answer:

No

Explanation:

Are the divisions of the electromagnetic spectrum distinct?

The answer is NO.

To explain my answer, there are some points to be noted

1.) There are no clear divisions between the different ranges or bands in the electromagnetic spectrum. The divisions are somewhat arbitrary

2.) The naming of subdivisions is also arbitrary. For instance, microwaves are sometimes regarded as a subdivision of radio waves

3.) The ranges of x-ray and gamma ray overlaps

7 0
3 years ago
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