-- If the system is 'closed', then nothing ... including energy ... can get in or out, and the total energy inside has to be constant.
If half of the energy in the system starts out as potential energy and the rest starts out as kinetic, and then the potential energy increases, there's only one place the increase could have come from ... it could only have been converted from kinetic energy. So the <em>kinetic energy</em> in the system <em>must</em> <em>decrease</em>.
In fact, this isn't even a "result". The kinetic energy has to decrease <em><u>before</u></em> the potential energy can increase, because that's where the increase has to come from.
If the system is 'open', then energy can come in and go out. If the potential energy inside suddenly increases, we don't know where it came from, so we can't say anything about what happens to the system.
Answer:
310.5 J
Explanation:
The total work done by Martha is equal to the increase in gravitational potential energy of the package, which is equal to
where
(mg) = 45 N is the weight of the package
is the increase in height of the package
The package is carried up 3 flights of stairs, each one with a height of 2.3 m, so the total increase in heigth is
And so, the work done by Martha is
For the answer to the question above,
the distance from i to j is 5 parts
(2 parts from i to k and 3 parts from k to j)
The y distance from i to j is
10 - 2 = 8
Each part is 8/5 = 1.6
Therefore the distance between the 2 parts from i to k is 3.2
From the y coordinate of I which is 2 plus the 3.2 to point k
2 + 3.2 = 5.2
Answer y =5.2
Now just convert that to fraction and that will be the answer
