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
It is false that scientific advances have led to decreased energy efficiency and waste reduction.
Answer:
The can mass is 0,00359 kg or 3,59 g
Explanation:
1. Relevant Data:
Steel thickness= 0.13 mm or 0.013 mm
h=11 cm
d=6 cm
ρ=800 kg/m^3
2. Calculate mass from densisty equation:
, then 
We need to estimate the volume of the can to calculate the mass.
3. Estimate volume using differentials:
Cylinder volume equation is:

Considering that the can is an object with a hole inside, then we need to estimate the real volume of the sheet of steel.
Using differentials we have:

Then, we could say that 
Replacing the values of d, h and dD, we obtain:


4. Calculate the mass
Convert volume unit into 

Calculate mass



Speaking bout mass,
it's mass is still 40Kg on the moon
but it's Weight on the moon is 1/6mg
Answer:
116.1 kgm²/s
1.12718 rad/s
Decreases
Explanation:
m = Mass of girl = 43 kg
M = Mass of roundabout = 120 kg
v = Velocity of roundabout = 2.7 m/s
r = Radius of roundabout = 1 m = R
I = Moment of inertia
Her angular momentum

Magnitude of angular momentum is 116.1 kgm²/s
Here the angular momentum is conserved

Angular speed of the roundabout is 1.12718 rad/s
Initial kinetic energy

Final kinetic energy

The overall kinetic energy decreases as can be seen. This loss is converted to heat.