The first one,second one and the forth one are correct
Answer:
a) 60 V
b) 125 V
c) 125 V
Explanation:
<u>Given</u>
We are given the total electric charge q = 6.75 nC = 6.75x 10^-9 C distributed uniformly over the surface of a metal sphere with a radius of R = 20.0 cm = 0.020 m.
<u>Required </u>
We are asked to calculate the potential at the distances
(a) r = 10.0 cm
(b) r = 20.0 cm
(c) r = 40.0 cm
<u>Solution</u>
(a) Here, the distance r > R so, we can get the potential outside the sphere (r > R) where the potential is given by
V = q/4
∈_o (1)
r is the distance where the potential is measured and the term 1/4
∈_o equals 9.0 x 10^9 Nm^2/C^2. Now we can plug our values for q and r into equation (1) to get the potential V where r = 0.10 m
V= 1*q/4
∈_o*r
=60 V
(b) Here the distance r is the same for the radius R, so we can get the potential inside the sphere (r = R) where the potential is given by
V = 1*q/4
∈_o*R (2)
Now we can plug our values for q and R into equation (2) to get the potential V where R = 0.20 m
V = 1*q/4
∈_o*R
= 125 V
(c) Inside the sphere the electric field is zero therefore, no work is done on a test charge that moves from any point to any other point inside the sphere. Thus the potential is the same at every point inside the sphere and is equal to the potential on the surface. and it will be the same as in part (b)
V= 125 V
A = 59.35cm
B = 196.56g
C = 74.65g
<u>Explanation:</u>
We know,

and L = x+y
1.
Total length, L = 100cm
Weight of Beam, W = 71.8g
Center of mass, x = 49.2cm
Added weight, F = 240g
Position weight placed from fulcrum, y = ?

Therefore, position weight placed from fulcrum is 59.35cm
2.
Total length, L = 100cm
Center of mass, x = 47.8 cm
Added weight, F = 180g
Position weight placed from fulcrum, y = 12.4cm
Weight of Beam, W = ?

Therefore, weight of the beam is 196.56g
3.
Total length, L = 100cm
Center of mass, x = 50.8 cm
Position weight placed from fulcrum, y = 9.8cm
Weight of Beam, W = 72.3g
Added weight, F = ?

Therefore, Added weight F is 74.65g
A = 59.35cm
B = 196.56g
C = 74.65g
I think it's 1.03412969 or 1.03