Answer:
Rubber is an insulator.
Explanation:
Rubber is an insulator. Electricity will always travel "the path of least resistance." Rubber has a very high resistance, so electricity will go somewhere else to find ground.
Newton's first law of motion is that an object in motion will tend to stay in motion unless an external force acts upon it.
Answer:
E = 0 r <R₁
Explanation:
If we use Gauss's law
Ф = ∫ E. dA =
/ ε₀
in this case the charge is distributed throughout the spherical shell and as we are asked for the field for a radius smaller than the radius of the spherical shell, therefore, THERE ARE NO CHARGES INSIDE this surface.
Consequently by Gauss's law the electric field is ZERO
E = 0 r <R₁
Answer:
D.None of these
Explanation:
The derivation of acceleration formula:
Let us call the 5kg mass
and the 4kg mass
. If the tension in the string is
then for the mass 
(1).
<em>(the negative sign on the right side indicates that acceleration is downwards)</em>
And for the mass 
(2).
<em> (the acceleration is upwards, hence the positive sign)</em>
Solving for
in the 2nd equation we get:
,
and putting this into the 1st equation we get:


Back to the question:
Using the formula for the acceleration we find


which is the acceleration that none of the given choices offer. Also, the acceleration of the two blocks is the same, because if it weren't, the difference in the instantaneous velocities of the objects would cause the string to break. Therefore, these two reasons make us decide that none of the choices are correct.
I think the answer is b, energy.