Friction<span> is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
Hope this is of great help to you, and happy studying~!
~Mistermistyeyed.</span>
128.1-127.8= 0.3Hz
<span>129.1-128.1= 1.0Hz </span>
<span>129.1-127.8= 1.3Hz</span>
Answer:
$900 trillion
Explanation:
If Alaska is 20% of the contiguous US, then the approximate area of interest is ...
1200 miles × 3000 miles = 3.6×10^6 square miles.
The size of a dollar bill is about ...
(6.5 cm)·(15.5 cm) = 100.75 cm^2
One mile is 160,934.4 cm, so 1 square mile is about ...
1 mi^2 = (160,934.4 cm)^2 ≈ 2.59·10^10 cm^2
The number of dollars of interest is then ...
(3.6 · 10^6 mi^2)(2.59 · 10^10 cm^2)/(100.75 cm^2) ≈ 9.3·10^14
≈ 930 × 10^12 . . . dollars
It would cost about 900 trillion dollars to cover the land area of the US in $1 bills.
Answer:
λ = 5.4196 10⁻⁷m, λ = 541.96 nm this is green ligh
Explanation:
The photoelectric effect was explained by Eintein assuming that the light was made up of particles called photons and these collided with the electrons taking them out of the material.
K = h f -Ф
where K is the kinetic energy of the ejected electrons, hf is the energy of the light quanta and fi is the work function of the material.
The speed of light is related to wavelength and frequency
c = λ / f
f = c /λ
we substitute
K = h c / λ - Φ
for the case that they ask us the kinetic energy of the electons is zero (K = 0)
h c / λ = Ф
λ = h c / Ф
we calculate
λ = 6.63 10⁻³⁴ 3 10⁸ / 3.67 10⁻¹⁸
λ = 5.4196 10⁻⁷m
let's take nm
lam = 541.96 nm
this is green light
