Who is a meteorologist
1 answer:
You might be interested in
Answer:
The Kinetic Energy INCREASE in the following situations:
a)A block slides down a frictionless incline:
e)A merry go round rotates faster due to the push by a person.
Explanation:
The energy kinetics is proportional to the square of the velocity:
We study the cases:
a)A block slides down a frictionless incline:
The gravity made a positive work and the box get a extra velocity, then the kinetics energy INCREASE
b)A box is pulled across a rough floor at constant speed:
The magnitude of the velocity does not change, so the kinetics energy does not change as well
c)A stone at the end of a string is whirled in a horizontal circle at constant speed:
The magnitude of the velocity does not change, so the kinetics energy does not change as well
d)A projectile approaches its maximum height:
If the projectile approaches its maximum height, its velocity approaches to zero. Then the kinetics Energy DECREASE
e)A merry go round rotates faster due to the push by a person.
Thanks to the push, the magnitude of the velocity INCREASE, so the kinetics energy INCREASE as well
Answer:
Sundial is an instrument showing the time by the shadow of a pointer cast by the sun on to a plate marked with the hours of the day.
Answer:
a) What are the characteristics of the radiation emitted by a blackbody?
The total emitted energy per unit of time and per unit of area depends in its temperature (Stefan-Boltzmann law).
The peak of emission for the spectrum will be displaced to shorter wavelengths as the temperature increase (Wien’s displacement law).
The spectral density energy is related with the temperature and the wavelength (Planck’s law).
b) According to Wien's Law, how many times hotter is an object whose blackbody emission spectrum peaks in the blue, at a wave length of 450 nm, than a object whose spectrum peaks in the red, at 700 nm?
The object with the blackbody emission spectrum peak in the blue is 1.55 times hotter than the object with the blackbody emission spectrum peak in the red.
Explanation:
A blackbody is an ideal body that absorbs all the thermal radiation that hits its surface, thus becoming an excellent emitter, as these bodies express themselves without light radiation, and therefore they look black.
The radiation of a blackbody depends only on its temperature, thus being independent of its shape, material and internal constitution.
If it is study the behavior of the total energy emitted from a blackbody at different temperatures, it can be seen how as the temperature increases the energy will also increase, this energy emitted by the blackbody is known as spectral radiance and the result of the behavior described previously is Stefan's law:
(1)
Where is the Stefan-Boltzmann constant and T is the temperature.
The Wien’s displacement law establish how the peak of emission of the spectrum will be displace to shorter wavelengths as the temperature increase (inversely proportional):
(2)
Planck’s law relate the temperature with the spectral energy density (shape) of the spectrum:
(3)
b) According to Wien's Law, how many times hotter is an object whose blackbody emission spectrum peaks in the blue, at a wavelength of 450 nm, than a object whose spectrum peaks in the red, at 700 nm?
It is need it to known the temperature of both objects before doing the comparison. That can be done by means of the Wien’s displacement law.
Equation (2) can be rewrite in terms of T:
(4)
Case for the object with the blackbody emission spectrum peak in the blue:
Before replacing all the values in equation (4), (450 nm) will be express in meters:
⇒
Case for the object with the blackbody emission spectrum peak in the red:
Following the same approach above:
⇒
Comparison:
The object with the blackbody emission spectrum peak in the blue is 1.55 times hotter than the object with the blackbody emission spectrum peak in the red.