Question

A pulley system operates with 40% efficiency. if the work put in is 200 joules, how much useful work is produced?

Answer 1

The useful work produced by a pulley system is 80 Joules.

Step-by-step explanation:

Efficiency is a measure of how much work is preserved in a process. The formula for efficiency is the energy output, divided by the energy input, expressed as a percentage. A perfect process would have an efficiency of 100%.

η = efficiency (Greek letter "eta")

Wo = the work or energy produced by a process. Units are Joules (J).

Wi = the work or energy put in to a process. Units are Joules (J).

`n = (Wo)/(Wi)`

`0.4 = (Wo)/(200J)`

Wo = 0.4*200J

Wo = 80 J

Answer 2

1. Efficiency is the measure of how efficient a process is. It is used to assess the ability of a process in avoiding waste energy, materials, money and time in doing a desirable output. It is calculated as;

Efficiency = useful energy ouput / total energy input

.40 = useful work / 200

useful work = 80 joules