Answer:
Therefore the work done is 640 ft pound.
Step-by-step explanation:
Given that, a heavy rope 40 ft long, weighs 0.8 lb/ft.
Force = weight.
Let we pull x ft. Then the remain rope = (40-x)ft.
(40-x) ft it is variable.
The weight of (40-x) ft is =(40-x)0.8 lb
∴ Force =(40-x)0.8 lb
Work done = Force × displacement
= (40-x)0.8 Δx [ displacement = Δx]
Therefore ΔW =(40-x)0.8 Δx
Since total rope is pulling up on the top of the building. Total displacement = 40 ft.
Total work done 
![=[32x-\frac{0.8x^2}{2}]_0^{40}](https://tex.z-dn.net/?f=%3D%5B32x-%5Cfrac%7B0.8x%5E2%7D%7B2%7D%5D_0%5E%7B40%7D)
![=[(32\times 40)-0.4(40)^2]](https://tex.z-dn.net/?f=%3D%5B%2832%5Ctimes%2040%29-0.4%2840%29%5E2%5D)
=640 ft pound.
Therefore the work done is 640 ft pound.
It is similar to an expresion just break it down x*2 is 5 nothing that is a whole number will complete this equation so the answer is 2.5
Since ABCD is parallelogram these rules apply:
Since
this implies that 
The answer is D.
Hope this helps.
r3t40
Answer:
i need to see a graph or the rest of the problem
Step-by-step explanation: