We know theory of relativity and refraction too.Theory of relativity states that speed of light is constant but according to ref
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Answer:
F = 263.51 N
Explanation:
given,
diameter of wheel = 78 cm
diameter of axle = 14.8 cm
Force exerted on the rim of wheel = 150 N
Force applied outside the axle = ?
To prevent rotation wheel from rotating the Force 'F' should be applied outside of the axle.
Net momentum about the center of mass should be zero
now,
Moment of about center due to 150 N = moment about center due to F on axle
7.4 F = 1950
F = 263.51 N
Hence, Force exerted outside of the axle in order to prevent the wheel from rotating is equal to 263.51 N.
a) E = 0
b)
Explanation:
a)
We can solve this problem using Gauss theorem: the electric flux through a Gaussian surface of radius r must be equal to the charge contained by the sphere divided by the vacuum permittivity:
where
E is the electric field
q is the charge contained by the Gaussian surface
is the vacuum permittivity
Here we want to find the electric field at a distance of
r = 12 cm = 0.12 m
Here we are between the inner radius and the outer radius of the shell:
However, we notice that the shell is conducting: this means that the charge inside the conductor will distribute over its outer surface.
This means that a Gaussian surface of radius r = 12 cm, which is smaller than the outer radius of the shell, will contain zero net charge:
q = 0
Therefore, the magnitude of the electric field is also zero:
E = 0
b)
Here we want to find the magnitude of the electric field at a distance of
r = 20 cm = 0.20 m
from the centre of the shell.
Outside the outer surface of the shell, the electric field is equivalent to that produced by a single-point charge of same magnitude Q concentrated at the centre of the shell.
Therefore, it is given by:
where in this problem:
is the charge on the shell
is the distance from the centre of the shell
Substituting, we find: