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
Answer:
Its mechanical energy is the same.
Explanation:
If forces are only conservative, the mechanical energy will be the same.
It can be different if energy get transformed in another kind of energy like elastic energy for example, although the amount of energy is always the same.
If we just have mechanical energy not geting transformed we have:
Em=K+U
Em: Mechanical energy
K: Kinetic energý
U: Potential energy
Then if Kinetic energy decreases 10J, Potential energy will grow up 10J to keep the same amount of mechanical energy.
Everywhere particles dont stay in one place they move elsewhere
Distance = (30+40+50) = 120 km
It's back where it started, so displacement = zero
Answer:
1. at least two charged interacting parts
2. from the electric fields of charged subatomic particles
3 an arrow released from the bow
4Electrical fields of charged particles interact, bonding those with opposite charges.
5 the interaction of the electric fields of protons and electrons
6 The energy stored in the system increases.
7 Kinetic energy increases because the magnets move in the direction of the field.
8 Iron pieces accelerate toward the magnet, and the energy stored in the system decreases.
9
The energy stored in the field decreases because the magnet moves in the direction of the field.
10 The energy stored increases and then decreases.
11 The wire was not connected to the source.
12 The electromagnet will become more powerful.
the rest are written, hope this helps (: