Answer:
KE + PE = KE + PE
Explanation:
In a closed system, the mechanical energy of the system is constant.
Mechanical energy is given by the sum of kinetic energy and potential energy; mathematically:
U = KE + PE
where
KE is the kinetic energy
PE is the potential energy
This means that if we consider two situations, one at the beginning and one at the end, the value of U will not change if the system is closed; this means that the sum KE + PE will remain the same, so we can write:
KE + PE = KE + PE
Answer:
Infinite Distance
Explanation:
The electric potential due to a point charge can be expressed by the following equation:

Here,
V is the electric potential due to the point charge
k is the proportionality constant
Q is the magnitude of the point charge
r is the distance from the charge
As the value of r increases, the value of V decreases since there is an inverse relation between the two. The value of V can be absolutely 0 when the distance from the charge is infinite i.e. r is infinite. Mathematically, dividing a number by infinity results in zero. Also theoretically speaking, at infinite distance the electric field lines won't approach and hence the electric potential would be zero.