An airplane traveling from San Francisco northeast to Chicago travels 1260 km in 3.5 h. What is the airplanes average velocity?
1 answer:
Answer:
Average velocity = 360km/h due Northeast.
Explanation:
Given the following data;
Distance = 1260km
Time = 3.5h.
Velocity =?
Velocity can be defined as the rate of change in displacement (distance) with time. Velocity is a vector quantity and as such it has both magnitude and direction.
Mathematically, velocity is given by the equation;
Substituting into the above equation;
Velocity, V = 360km/h.
Since velocity is a vector quantity, it must have both magnitude and direction.
<em>Hence, the average velocity of the airplane is 360km/h due Northeast. </em>
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Answer:
9.98 × 10⁻⁹ C
Explanation:
mass, m = 1.00 × 10⁻¹¹ kg
Velocity, v = 23.0 m/s
Length of plates D₀ = 1.80 cm = 0.018 m
Magnitude of electric field, E = 8.20 × 10⁴ N/C
drop is to be deflected a distance d = 0.290 mm = 0.290 × 10⁻³ m
density of the ink drop = 1000 kg/m^3
Now,
Time =
or
Time =
or
Time = 6.9 × 10⁻⁴ s
Now, force due to the electric field, F = q × E
where, q is the charge
Also, Force = Mass × acceleration
q × E = 1.00 × 10⁻¹¹ × a
or
a =
Now from the Newton's equation of motion
where,
d is the distance
u is the initial speed
a is the acceleration
t is the time
or
or
q = 9.98 × 10⁻⁹ C
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.