B. wind.
Sun (solar) --> plants (photosynthesis) --> cola (chemical) --> heat (combustion) --> steam --> turbine (kinetic) --> generator (electric)
There is no wind.
Answer:
DONORS: If the material for which it substitutes has more electrons than the original
ACCEPTORS: If the replacement material has fewer electrons than the original material
Fermi level: the point where the probability of finding the last electron is ½
Explanation:
When in a semiconductor material a small fraction of an element is replaced by another with different valences, an excess charge is created.
If the material for which it substitutes has more electrons than the original, there is an excess of electrons, these excess electrons are weakly bound in the material and their orbits are large, in an energy versus moment diagram their energy places them a little more below the conduction band, these materials are called DONORS.
If the replacement material has fewer electrons than the original material, one electron is missing to complete the bonds, so there is a movement of the other electrons, an easier way to analyze this movement of the (n-1) electrons is to suppose that The missing charge has a positive charge and to study its movement, this positive charge is called a hole, its binding energy is small so the orbit of the hole is large, in an energy diagram it is located a little above the band of valence, these are called ACCEPTORS
The Fermi level is defined as the point where the probability of finding the last electron is ½, when the temperature is changed the density of states of the bands changes, therefore the location point moves, but its [probability remains ½
Answer: 6m/s
Explanation:
Using the law of conservation of momentum, the change in momentum of the bodies before collision is equal to the change in momentum after collision.
After collision, the two objects will move at the same velocity (v).
Let mA and mB be the mass of the two objects
uA and uB be their velocities before collision.
v be their velocity after collision
Since the two objects has the same mass, mA= mB= m
Also since object A is at rest, its velocity = 0m/s
Velocity of object B = 12m/s
Mathematically,
mAuA + mBuB = (mA+mB )v
m(0) + m(12) = (m+m)v
0+12m = (2m)v
12m = 2mv
12 = 2v
v = 6m/s
Therefore the speed of the composite body (A B) after the collision is 6m/s
Answer:
2m₁m₃g / (m₁ + m₂ + m₃)
Explanation:
I assume the figure is the one included in my answer.
Draw a free body diagram for each mass.
m₁ has a force T₁ up and m₁g down.
m₂ has a force T₁ up, T₂ down, and m₂g down.
m₃ has a force T₂ up and m₃g down.
Assume that m₁ accelerates up and m₂ and m₃ accelerate down.
Sum of the forces on m₁:
∑F = ma
T₁ − m₁g = m₁a
T₁ = m₁g + m₁a
Sum of the forces on m₂:
∑F = ma
T₁ − T₂ − m₂g = m₂(-a)
T₁ − T₂ − m₂g = -m₂a
(m₁g + m₁a) − T₂ − m₂g = -m₂a
m₁g + m₁a + m₂a − m₂g = T₂
(m₁ − m₂)g + (m₁ + m₂)a = T₂
Sum of the forces on m₃:
∑F = ma
T₂ − m₃g = m₃(-a)
T₂ − m₃g = -m₃a
a = g − (T₂ / m₃)
Substitute:
(m₁ − m₂)g + (m₁ + m₂) (g − (T₂ / m₃)) = T₂
(m₁ − m₂)g + (m₁ + m₂)g − ((m₁ + m₂) / m₃) T₂ = T₂
(m₁ − m₂)g + (m₁ + m₂)g = ((m₁ + m₂ + m₃) / m₃) T₂
m₁g − m₂g + m₁g + m₂g = ((m₁ + m₂ + m₃) / m₃) T₂
2m₁g = ((m₁ + m₂ + m₃) / m₃) T₂
T₂ = 2m₁m₃g / (m₁ + m₂ + m₃)
I would say it’s “B” for the reason that the student did not experiment with a short ramp and large ball as well as a large ramp and a short ball. They have to do those experiments as well before drawing their conclusion.
