Answer:
a) 2.85 kW
b) $ 432
c) $ 76.95
Explanation:
Average price of electricity = 1 $/40 MJ
Q = 20 kW
Heat energy production = 20.0 KJ/s
Coefficient of performance, K = 7
also
K=(QH)/Win
Now,
Coefficient of Performance, K = (QH)/Win = (QH)/P(in) = 20/P(in) = 7
where
P(in) is the input power
Thus,
P(in) = 20/7 = 2.85 kW
b) Cost = Energy consumed × charges
Cost = ($1/40000kWh) × (16kW × 300 × 3600s)
cost = $ 432
c) cost = (1$/40000kWh) × (2.85 kW × 200 × 3600s) = $76.95
1) A negatively charged ion is chloride
2) Moving from left to right, valence electrons increase by one.
3) The period number gives information about how many energy levels it has
4) Fluorine has a charge of 1–
5) Potassium and iodine form an ionic bond
The periodic table is an arrangement of elements into groups and periods based on their periodic properties.
In the periodic table, elements are arranged in groups and periods. There are 18 groups and 8 periods.
Chlorine is in group 17, there have seven outermost electrons hence the chlorine atom needs only one more electron in order to attain a stable octet. This is done by accepting one electron to form the negatively charged chloride ion.
As we move from one period to another, one extra electron is added to the outermost shell of elements. Hence, the valence electrons increases by one.
The period to which an element belongs shows you the number of shells or energy levels in the atom of that element.
Fluorine is in group 17. One electron is needed to achieve a stable octet. When an atom accepts one electron, its charge is 1–.
Bonding based on ionic charges occurs between metals and nonmetals. Potassium is a metal of group 1 and iodine is a non metal of group 17 hence they can bond together based on their ionic charges.
Learn more:brainly.com/question/23277186
Answer:
The total work done by friction is -2 · μ · m · g · D
Explanation:
Hi there!
The work done by a force is calculated as follows:
W = F · d · cos θ
Where:
W = work.
F = force that does the work.
d = displacement.
θ = angle between the displacement and the force.
If the force is horizontal, as in this case, cos θ = 1
The friction force is calculated as follows:
Ffr = μ · m · g
Where:
μ = friction coefficient.
m = mass of the object.
g = acceleration due to gravity.
Then, in this case, the work done by friction when pushing the block from A to B will be:
W AB = -Ffr · D
W AB = - μ · m · g · D
Notice that the friction force is negative because it is opposite to the pushing force P.
When the block is pushed from B to A, the work done by friction will be:
W BA = Ffr · (-D)
W BA = -μ · m · g · D
Now, the displacement is negative and the friction force is positive (in the opposite direction to -P).
The total work done by friction will be:
W AB + W BA = - μ · m · g · D - μ · m · g · D = -2 μ · m · g · D
Answer:
0.4
Explanation:
F-Fr=ma where F is applied force, Fr is friction, m is mass and a is acceleration.
Since the mass is moving with a constant velocity, there's no acceleration hence
where N is the weight of object and \mu is coefficient of kinetic friction.
![F=\mu N and making [tex]\mu](https://tex.z-dn.net/?f=F%3D%5Cmu%20N%20and%20making%20%5Btex%5D%5Cmu)
the subject
Substituting F for 8 N and N for 20 N
Therefore, coefficient of kinetic friction is 0.4
