The second one, air is a poor conductor. If it weren't it wouldn't be used as such in construction. It's not the best insulator, but is quite efficient, and much cheaper to include a layer of air inside a wall than to add additional layers of asbestos :)
Answer:

Explanation:
Let's use Ohm's law:
or
(1)
Where:

We know the value of the voltage V, so we need to find the value of R in order to find I. Fortunately there is a relation between the resistivity of a conductor and its electrical resistance given by:
(2)
Where:

Keep in mind that the electrical resistivity of the gold is a known constant which is
and the cross sectional area of the conductor is calculated as:

Because we have a wire in this case, so we assume a cylindrical geometry.
Now replacing our data in (2)

Finally, we know R and V, so replacing these values in (1) we will be able to find the current:

Answer: C. 8.0 m west
Explanation: The arrows are going 15 m west and 7.0 m east. 7 meters of the west will cancel out because 15-7=8. Subtract the smaller number from the bigger number, which is west minus east. The answer will be 8.0 m west.
Answer:
Explanation:
Given
mass of person
=68 kg
car dips about 1.2 cm
We know
F=kx
Where k=combined spring constant
mg=kx



Answer:
Part a)

Part B)

Explanation:
As we know that when both the forces are acting on the object in same direction then we will have

as we know that

m = 10.6 kg
now we will have


Now two forces are in opposite direction then we have


Part A)
Now we will have from above two equation

Part B)
Similarly for other force we have
