Answer:
the photons (quanta of light) collide with the electrons, these electrons have to overcome the threshold energy that is the energy of union with the metal, and the energy that remains is converted to kinetic energy.
K = E - Ф
Explanation:
The photoelectric effect is the emission of electrons from the surface of a metal.
This was correctly explained by Einstein, in his explanation the energy of the photons (quanta of light) collide with the electrons, these electrons have to overcome the threshold energy that is the energy of union with the metal, and the energy that remains is converted to kinetic energy.
E = hf
E = K + Ф
K = E - Ф
The energy of the photons is given by the Planck relation E = hf and according to Einstein the number of joints must be added
E = n hf
Therefore, depending on the value of this energy, the emitted electrons can have energy from zero onwards.
The speed of the boy and his friend at the bottom of the slope is 16.52 m/s.
<h3>Their speed at the bottom</h3>
Apply the principle of conservation of energy,
E(up) - E(friction) = E(bottom)
mg sin(15) + ¹/₂(M + m)u² - μ(M + m)cos 15 = ¹/₂(M + m)v²
![v = \sqrt{2[\frac{mgd \ sin15 \ + \frac{1}{2}(M + m)u^2 \ -\mu (M + m)g cos\ 15 }{M + m}] }](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B2%5B%5Cfrac%7Bmgd%20%5C%20sin15%20%5C%20%2B%20%5Cfrac%7B1%7D%7B2%7D%28M%20%2B%20m%29u%5E2%20%5C%20-%5Cmu%20%28M%20%2B%20m%29g%20cos%5C%2015%20%7D%7BM%20%2B%20m%7D%5D%20%7D)
where;
- u is the speed of the after 28 m
u = √2gh
u = √(2gL sin15)
u = √(2 x 9.8 x 28 x sin 15)
u = 11.92 m/s
![v = \sqrt{2[\frac{(30)(9.8)(70) \ sin15 \ + \frac{1}{2}(30 + 50)(11.92)^2 \ - 0.12 (30 + 50)9.8 cos\ 15 }{30 + 50}] }\\\\v = 16.52 \ m/s](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B2%5B%5Cfrac%7B%2830%29%289.8%29%2870%29%20%5C%20sin15%20%5C%20%2B%20%5Cfrac%7B1%7D%7B2%7D%2830%20%2B%2050%29%2811.92%29%5E2%20%5C%20-%200.12%20%2830%20%2B%2050%299.8%20cos%5C%2015%20%7D%7B30%20%2B%2050%7D%5D%20%7D%5C%5C%5C%5Cv%20%3D%2016.52%20%5C%20m%2Fs)
Thus, the speed of the boy and his friend at the bottom of the slope is 16.52 m/s.
Learn more about speed here: brainly.com/question/6504879
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Answer:
1. Police Weren't Able To Find Any Real Leads
2. They Didn't Find Any Clues To The Killer Until 18 Years Later
Explanation:
It was unknown at the time, but it would go on to take 18 years for her killer to be arrested and tried for her death. The initial case went on from 1995 to 1997 but ended up closing when the police department was unable to find any real leads.
Answer:magnitude -5; angle 160°
Explanation:
Vector A is described as having magnitude 5 and angle -20°.
To get an equivalent vector, we either leave the magnitude at 5 and add 360° to the angle, or we reverse the magnitude to -5 and add 180° to the angle.
5 @ -20° = 5 @ 340°
5 @ -20° = -5 @ 160°
The third one is the answer.
