1) The heat added to system
2) 800J
3) I'm not sure but I think it would be 300J.. Not certain tho
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

Electromagnetic waves do not require a medium to travel through. They can travel through empty space or matter.
The answer is emagination emagination