A student walks downstairs to class. Which statement correctly describes the types of energy the student has at the top of the s
1 answer:
Answer:
D potential energy at the top of the stairs, kinetic energy as she walks down
Explanation:
The potential energy of a body is the energy due to the position of the body.
At the top of the stair case, the student is at a significant height.
Kinetic energy is the energy due to the motion of the body.
As the student descends, the potential energy is changed to kinetic energy.
To find the potential energy;
P.E = mgH
m is the mass
g is the acceleration due to gravity
H is the height of the body
To find the kinetic energy;
K.E = m v²
m is the mass
v is the velocity
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Missing part in the text of the problem:
"<span>Water is exposed to infrared radiation of wavelength 3.0×10^−6 m"</span>
First we can calculate the amount of energy needed to raise the temperature of the water, which is given by
where
m=1.8 g is the mass of the water
is the specific heat capacity of the water
is the increase in temperature.
Substituting the data, we find
We know that each photon carries an energy of
where h is the Planck constant and f the frequency of the photon. Using the wavelength, we can find the photon frequency:
So, the energy of a single photon of this frequency is
and the number of photons needed is the total energy needed divided by the energy of a single photon:
"<span>Water is exposed to infrared radiation of wavelength 3.0×10^−6 m"</span>
First we can calculate the amount of energy needed to raise the temperature of the water, which is given by
where
m=1.8 g is the mass of the water
Substituting the data, we find
We know that each photon carries an energy of
where h is the Planck constant and f the frequency of the photon. Using the wavelength, we can find the photon frequency:
So, the energy of a single photon of this frequency is
and the number of photons needed is the total energy needed divided by the energy of a single photon: