Suppose that the cyclist begins his journey from the rest from the top of a wedge with a slope of a degree above the horizontal.
At point A (where it starts its journey), the energy is:
Ea = m * g * h
In other words, energy is only potential.
At point B (located at the bottom of the wedge), the energy is:
Eb = (1/2) * (m) * (v ^ 2)
In other words, the energy is only kinetic.
For energy conservation we have:
Ea = Eb
That is, we have that all potential energy is transformed into kinetic energy.
Which means that the cyclist has less kinetic energy at point A because that's where he has more potential energy.
answer:
the cyclist has less kinetic energy at point A because that's where he has more potential energy.
Explanation:
Exothermic reaction is defined as the reaction in which release of heat takes place. This also means that in an exothermic reaction, bond energies of reactants is less than the bond energies of products.
Hence, difference between the energies between the reactants and products releases as heat and therefore, enthalpy of the system will decrease.
Whereas in an endothermic reaction, heat is supplied from outside and absorbed by the reactant molecules. Hence, enthalpy of the system increases.
As water acts as a coolent and when fuel rods in a nuclear reactor are immersed in it then heat created by coolent is absorbed by water and then it changes into steam.
Since, absorption of heat occurs in the nuclear reactor. Therefore, it is an endothermic reaction.
Thus, we can conclude that nuclear reactors use fuel rods to heat water and generate steam. This process is endothermic.
What are you talking about
A) ![5.0\cdot 10^{-11} m](https://tex.z-dn.net/?f=5.0%5Ccdot%2010%5E%7B-11%7D%20m)
The energy of an x-ray photon used for single dental x-rays is
![E=25 keV = 25,000 eV \cdot (1.6\cdot 10^{-19} J/eV)=4\cdot 10^{-15} J](https://tex.z-dn.net/?f=E%3D25%20keV%20%3D%2025%2C000%20eV%20%5Ccdot%20%281.6%5Ccdot%2010%5E%7B-19%7D%20J%2FeV%29%3D4%5Ccdot%2010%5E%7B-15%7D%20J)
The energy of a photon is related to its wavelength by the equation
![E=\frac{hc}{\lambda}](https://tex.z-dn.net/?f=E%3D%5Cfrac%7Bhc%7D%7B%5Clambda%7D)
where
is the Planck constant
is the speed of light
is the wavelength
Re-arranging the equation for the wavelength, we find
![\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{4\cdot 10^{-15}J}=5.0\cdot 10^{-11} m](https://tex.z-dn.net/?f=%5Clambda%3D%5Cfrac%7Bhc%7D%7BE%7D%3D%5Cfrac%7B%286.63%5Ccdot%2010%5E%7B-34%7D%20Js%29%283%5Ccdot%2010%5E8%20m%2Fs%29%7D%7B4%5Ccdot%2010%5E%7B-15%7DJ%7D%3D5.0%5Ccdot%2010%5E%7B-11%7D%20m)
B) ![2.0\cdot 10^{-11} m](https://tex.z-dn.net/?f=2.0%5Ccdot%2010%5E%7B-11%7D%20m)
The energy of an x-ray photon used in microtomography is 2.5 times greater than the energy of the photon used in part A), so its energy is
![E=2.5 \cdot (4\cdot 10^{-15}J)=1\cdot 10^{-14} J](https://tex.z-dn.net/?f=E%3D2.5%20%5Ccdot%20%284%5Ccdot%2010%5E%7B-15%7DJ%29%3D1%5Ccdot%2010%5E%7B-14%7D%20J)
And so, by using the same formula we used in part A), we can calculate the corresponding wavelength:
![\lambda=\frac{hc}{E}=\frac{(6.63\cdot 10^{-34} Js)(3\cdot 10^8 m/s)}{1\cdot 10^{-14}J}=2.0\cdot 10^{-11} m](https://tex.z-dn.net/?f=%5Clambda%3D%5Cfrac%7Bhc%7D%7BE%7D%3D%5Cfrac%7B%286.63%5Ccdot%2010%5E%7B-34%7D%20Js%29%283%5Ccdot%2010%5E8%20m%2Fs%29%7D%7B1%5Ccdot%2010%5E%7B-14%7DJ%7D%3D2.0%5Ccdot%2010%5E%7B-11%7D%20m)