A small piece of aluminum (atomic number 13) contains 10^15 atoms (The atomic number is the number of protons; it determines the
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Answer:
Explanation:
Answer:
-320 μJ.
Explanation:
Consider a point with an electrical charge of . Assume that
is the electrical potential at the position of that charge. The electrical potential of that point charge will be equal to:
.
Keep in mind that since both and
might not be positive, the size of the electrical potential energy might not be positive, either.
For this point charge,
; (that's -8.0 microjoules, which equals to
)
.
Hence its electrical potential energy:
.
Why is this value negative? The electrical potential energy of a charge is equal to the work needed to bring that charge from infinitely far away all the way to its current position. Also, negative charges are attracted towards regions of high electrical potential. Bringing this negative charge to the origin will not require any external work. Instead, this process will release 320 μJ of energy. As a result, the electrical potential energy is a negative value.
car starts from rest
final speed attained by the car is
acceleration of the car will be
now the time to reach this final speed will be
so it required 1.39 s to reach this final speed