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

Answer:
a = 2.94 m/s²
Explanation:
In order for the cup not to slip, the unbalanced force on cup must be equal to the frictional force:
Unbalanced Force = Frictional Force
ma = μR = μW
ma = μmg
a = μg
where,
a = maximum acceleration for the cup not to slip = ?
μ = coefficient of static friction = 0.3
g = acceleration due to gravity = 9.8 m/s²
Therefore,
a = (0.3)(9.8 m/s²)
<u>a = 2.94 m/s²</u>
It doesn't mean that the climate is changing, it is probably just the morning dew.
C. The opportunity cost of a student who is staying up all night to study for an exam that he has to take in the early morning is sleep or rest.
<h3>
What is law of opportunity cost?</h3>
The law of increasing opportunity cost is an economic principle that describes how opportunity costs increase as resources are applied.
As the student gives up his sleep or night rest in the place of his exam preparation, we say that the opportunity cost is the sleep or rest.
Thus, the opportunity cost of a student who is staying up all night to study for an exam that he has to take in the early morning is sleep or rest.
Learn more about opportunity cost here: brainly.com/question/8846809
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