Answer:
a) R = ρ₀ L /π(r_b² - R_a²)
, b) ρ₀ = V / I π (r_b² - R_a²) / L
Explanation:
a) The resistance of a material is given by
R = ρ l / A
where ρ is the resistivity, l is the length and A is the area
the length is l = L and the resistivity is ρ = ρ₀
the area is the area of the cylindrical shell
A = π r_b² - π r_a²
A = π (r_b² - r_a²)
we substitute
R = ρ₀ L /π(r_b² - R_a²)
b) The potential difference is related to current and resistance by ohm's law
V = i R
we subsist the expression of resistance
V = I ρ₀ L /π (r_b² - R_a²)
ρ₀ = V / I π (r_b² - R_a²) / L
How much gravitational potential energy does the block have
when it gets to the top of the ramp ?
(weight) x (height) = (15 N) x (0.2 m) = 3 Joules .
If there were no friction, you would only need to do 3 Joules of work
to lift the block from the bottom to the top.
But the question says you actually have to do 4 Joules of work
to get the job done.
Friction stole one of your Joules along the way.
Choice-4 is not the correct one.
Choice-1 is the correct one.
===========================
Notice that the mass of the block is NOT 15 kg , and you
don't have to worry about gravity to answer this question.
The formula for potential energy is (m)·(g)·(h) .
But (m·g) is just the WEIGHT, and the formula
is actually (weight)·(height).
The question GIVES us the weight of the block . . . 15 N .
So the potential energy at the top is just (15N)·(0.2m) = 3 Joules.
Answer:
the decrease in energy is due to a transformational in internal energy of the body in the rebound.
Explanation:
For this exercise we can calculate the initial and final mechanical energy
Em₀ = U = m g y₁
= U = m g y₂
we look for the variation of the energy
ΔEm = Em_{f} - Em₀
ΔEm = m g (y_{f} -y₀)
ΔEm = m g (0.86 -1.2)
ΔEm = -3.332 m
We can see that there is a decrease in mechanical energy, this is transformed into internal energy of the ball during the impact with the ground, this energy can be formed by several factors such as a part of the friction with the surface, an increase in body temperature or a deformation of the body; there may be a contribution from several of these factors.
In conclusion the decrease in energy is due to a transformational in internal energy of the body in the rebound.
The answer is negative reinforcement. It is because negative reinforcement is where a particular behavior of a person is being stopped or being prevented in a way to prevent of producing an outcome that would likely be considered as negative. It could be seen above as Kendra avoids doing her used to behavior just to prevent herself from having no television which would be a negative outcome if it happens.
