The resistance of a conductor is given by:

where

is the resistivity of the material
L is the length of the conductor
A is its cross-sectional area
We can use this formula to solve both parts of the problem.
a) The length of the copper wire is L=1.0 m. Its diameter is d=0.50 mm, so its radius is

And its cross-sectional area is

The copper resistivity is

, therefore the resistance of this piece of wire is

b) The length of this piece of iron is L=10 cm=0.10 m. Its cross-sectional size is L=1.0 mm=0.001 m, so its cross-sectional area is

The iron resistivity is

, therefore the resistance of this piece of wire is
Friction is the force that is resisting the motion of an object so it will always point in the opposite direction of that of movement. ... The force of gravity points downwards . So when you do work against gravity it means that the force acting on that object points in the upward direction .
Yes the temp should be changed
Observe that the given vector field is a gradient field:
Let
, so that



Integrating the first equation with respect to
, we get

Differentiating this with respect to
gives

Now differentiating
with respect to
gives

Putting everything together, we find a scalar potential function whose gradient is
,

It follows that the curl of
is 0 (i.e. the zero vector).