A)<span>
dQ = ρ(r) * A * dr = ρ0(1 - r/R) (4πr²)dr = 4π * ρ0(r² -
r³/R) dr
which when integrated from 0 to r is
total charge = 4π * ρ0 (r³/3 + r^4/(4R))
and when r = R our total charge is
total charge = 4π*ρ0(R³/3 + R³/4) = 4π*ρ0*R³/12 = π*ρ0*R³ / 3
and after substituting ρ0 = 3Q / πR³ we have
total charge = Q ◄
B) E = kQ/d²
since the distribution is symmetric spherically
C) dE = k*dq/r² = k*4π*ρ0(r² - r³/R)dr / r² = k*4π*ρ0(1 -
r/R)dr
so
E(r) = k*4π*ρ0*(r - r²/(2R)) from zero to r is
and after substituting for ρ0 is
E(r) = k*4π*3Q(r - r²/(2R)) / πR³ = 12kQ(r/R³ - r²/(2R^4))
which could be expressed other ways.
D) dE/dr = 0 = 12kQ(1/R³ - r/R^4) means that
r = R for a min/max (and we know it's a max since r = 0 is a
min).
<span>E) E = 12kQ(R/R³ - R²/(2R^4)) = 12kQ / 2R² = 6kQ / R² </span></span>
Answer:
the answer the correct one is c
Explanation:
Electric charges of different signs attract and those of the same sign repel. In addition, there are two types of insulating bodies, where the loads are fixed (immobile) and metallic (with mobile loads.
Let's analyze the situation presented
* A rod with positive approaches and the sphere is attracted, so the charge on the sphere is negative
* A rod with a negative charge approaches and the sphere is attracted, therefore the charge of the sphere must be positive.
For this to happen, the sphere must be unloaded and the charge that creates the phenomenon are induced charges because the mobile charges of the same sign as the sphere are repelled.
when checking the answer the correct one is c
Answer:
Explanation:
a) R = V/I = 0.7/0.022 = 32Ω
b) R = V/I = 0.6/0.005 = 120Ω
c) No...Current change is not linear with voltage change.
Answer:
further tightening is required.
Explanation:
The beat created / sec = difference of frequencies
Initial beat heard = 2
so difference of frequencies = 2
after tightening beat heard = 1
difference of frequencies decreases because frequency of tuning fork was higher than piano sound.
on further tightening difference decreases because tightening increases the frequency of piano hence further tightening is required for resonance.
Answer:
a = - 0.209 [m/s²]
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
We will take the positive forces to the right and the negative forces to the left.
![155-277+113=43*a\\-9=43*a\\a = - 0.209[m/s^{2} ]](https://tex.z-dn.net/?f=155-277%2B113%3D43%2Aa%5C%5C-9%3D43%2Aa%5C%5Ca%20%3D%20-%200.209%5Bm%2Fs%5E%7B2%7D%20%5D)
The negative sign means that the box accelerates in a negative direction to the left.
