Answer:
<h2>A. a spring & B. a well dried into an aquifer.</h2>
Because metallic bonds involve all of the metal atoms in a piece of metal sharing all of their valence electrons with "delocalized" bonds.
Answer:
a) The electric field at that point is 
newtons per coulomb.
b) The electric force is 
newtons.
Explanation:
a) Let suppose that electric field is uniform, then the following electric field can be applied:
(1)
Where:
- Electric field, measured in newtons per coulomb.
- Electric force, measured in newtons.
- Electric charge, measured in coulombs.
If we know that 
and 
, then the electric field at that point is:
The electric field at that point is newtons per coulomb.
b) If we know that and 
, then the electric force is:
The electric force is newtons.
Answer:
(d) a net external force must be acting on the system
Explanation:
Momentum is given as the product of mass and velocity.
P = MV
According to Newton's second law of motion, " Force applied to a body (system) is directly proportional to the rate of change of momentum of the body (system) which takes place in the direction of the applied force (external force).
F ∝ΔMV
Therefore, If the total momentum of a system is changing, a net external force must be acting on the system.
(d) a net external force must be acting on the system
