A heavy rope, 40 ft long, weighs 0.8 lb/ft and hangs over the edge of a building 110 ft high. How much work is done in pulling the rope to the top of the building

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

                            =640 ft pound.

Therefore the work done is 640 ft pound.

4 candies

step-by-step explanation:

7 x 28 = 196

200 - 196 = 4 candies remaining.

e^-kt = n/n0 = 0.79  

-kt = ln 0.79  

t = - ln 0.79/0.0001  

= 2357 years

step-by-step explanation: