Question

A pulley system has an efficiency of 81.8%. If you perform 1100 J of work,

how much useful work does the pulley perform?

Answer 1

The useful work performed by the pulley is, E = 899.8 J

Step-by-step explanation:

Given data,

The efficiency of a pulley, Ef = 81.8 %

The work input,
`W_(i)` = 1100 J

The main purpose of the pulley is to change the direction of the force applied.

The formula for useful energy,

`E=(E_(f) )/(100)* W_(i)`

`E=(81.8)/(100)*1100`

E = 899.8 J

Hence, the useful work performed by the pulley is, E = 899.8 J

Answer 2

Useful Work = 899.8 J

Step-by-step explanation:

Efficiency =
`\mathbf{(Useful \ Work)/(Total \ Work)*100}`

Useful Work =
`\mathbf{(Efficiency* Total \ Work)/(100)}`

Useful Work =
`\mathbf{(81.8*1100)/(100)}`

Useful Work = 899.8 J

Therefore the amount of useful work done out of total work of 1100 J is 899.8 J by the pulley.