B. surface wave because it is a mechanical energy
Explanation:
(a) From E=
r
2
k
e
Q
Q=
k
e
Er
2
=
(8.99×10
9
N⋅m
2
/C
2
)
(8.90×10
2
N/C)(0.750m)
2
=5.57×10
−8
C
But Q is negative since
E
→
points inward, so
Q=−5.57×10
−8
C=−55.7nC
(b) The negatve charge has a spherically symmetric charge distribution, concentric with the spherical shell
Answer:
3.99*10^-3N/C
Explanation:
Using
Ep= kq/r²
Where r = 0.6mm = 0.6*10^-3m
K= 8.9*10^9 and q= 1.6*10^-19
So = 8.9*10^9 * 1.6*10^-19/0.6*10^-3)²
= 3.99*10^-3N/C
Answer:
w = 0.55 rad / s
Explanation:
For this exercise let's use the conservation of angular momentum, let's write the moment in two moments
Initial
L₀ = r p + 0
L₀ = r mv
The first term is the angular momentum of the mass
Final
Lf = (I + m r²) w
Where I is the moment of inertia of the stool and the other term is the moment of inertia of the mass
L₀ = Lf
r mv = (I + m r²) w
w = m r v / (I + m r²)
Let's calculate
w = 2.0 0.45 3.0 / (4.5 + 2.0 0.45²)
w = 2.7 / 4.9
w = 0.55 rad / s
Not sure the precise concept of "normal observation", but I assume that is observed by "eyes".
Eye observation is basically macroscopic, but when you use a mark, which can be regarded as a point of mass, then it goes to microscopic.
Mark is a reference point which you can compare the relative position change, but with your eyes, first you cannot notice microscopic changes, second the eyes cannot precisely set a stable reference point.
