photons and convection - density differences makes bubbles of hot stuff float up. pretty sure
Answer:
See explanation
Explanation:
A change in momentum occurs when a force is applied to an object and changes its velocity.
100/5= 20, 20 seconds is the time needed.
Answer:

Explanation:
Needed torque can be estimated by means of the Theorem of Angular Momentum Conservation and Impact Theorem. The center of mass of the system is:


Let assume that both masses can be modelled as particles, then:
![[(1.51\,kg)\cdot (0.923\,m)^{2} + (1.97\,kg)\cdot (0.707\,m)^{2}]\cdot (38\,\frac{rev}{min} )\cdot (\frac{2\pi\,rad}{1\,rev} )\cdot (\frac{1\,min}{60\,s} ) -T\cdot (7.5\,s) = 0\,\frac{kg\cdot m^{2}}{s}](https://tex.z-dn.net/?f=%5B%281.51%5C%2Ckg%29%5Ccdot%20%280.923%5C%2Cm%29%5E%7B2%7D%20%2B%20%281.97%5C%2Ckg%29%5Ccdot%20%280.707%5C%2Cm%29%5E%7B2%7D%5D%5Ccdot%20%2838%5C%2C%5Cfrac%7Brev%7D%7Bmin%7D%20%29%5Ccdot%20%28%5Cfrac%7B2%5Cpi%5C%2Crad%7D%7B1%5C%2Crev%7D%20%29%5Ccdot%20%28%5Cfrac%7B1%5C%2Cmin%7D%7B60%5C%2Cs%7D%20%29%20-T%5Ccdot%20%287.5%5C%2Cs%29%20%3D%200%5C%2C%5Cfrac%7Bkg%5Ccdot%20m%5E%7B2%7D%7D%7Bs%7D)
The torque needed to stop the system is:

Answer:
The answer is explained below.
Explanation:
The energy emitted during the de-excitation of an electron from a higher energy level to a lower energy level is directly proportional to the frequency of the emitted light.
Here, the total sum of the energies of 2 frequencies of light emitted in different stages is equal to the energy of a single frequency of light during the de-excitation of fourth level to ground level directly.
Hence the total sum of of the frequencies of 2 lights emitted in different stages is equal to the frequency of single frequency of light emitted during the de-excitation from fourth level to ground level directly.
The some of the energies of 2 frequencies emitted by one electron is equal to the energy of a single frequency when electron jumps directly.