A 200-foot cable weighing 800 pounds is hanging from a winch 200 feet above ground level. (a) How much per foot does this cable weigh? if a piece of this cable is A. x long, what is the weigh of this piece?
(b) Find the work (in ft-lb) done in winding up the cable when there is a 400- pound load attached to the end of the cable.

4 pd / ft

140000 ft/pd

Step-by-step explanation:

Total Weight of cable = 800 pounds

Length of cable = 200 feets

Weight per foot = Total weight / length = 800 / 200 = 4 pounds per foot

Weight of piece will be :

Weight of cable - weight per foot * x

800 - 4x

Workdone with 300 pound load attached :

∫f(x)

f(x) = (800+300 - 4x) = 1100 - 4x

∫1100 - 4xdx at 200 to 0

Integrating the above

1100x - 4/2x² at x = 200 to 0

1100x - 2x²

1100(200) - 2(200²) - 1100(0) + 2(0^²))

(220000-80000) - 0 + 0

140000 ft/pd

option 3 . (5x + 1) - (-10x + 6)

step-by-step explanation:

option 1 :

(4x + 3) + (-9x + 4)

or 4x+3 -9x + 4

or -5x + 7

option 2

(x - 2) - (6x - 9)

or x-2-6x + 9

or -5x + 7

option 3

(5x+ + 6)

or 5x + 1 + 10x -6

or 15x -5

option 4

-4x+2x+7-3x

-7x + 2x + 7

-5x + 7

hence only option 3 did   not satisfy the given simplify expression.

no idea

step-by-step explanation: