Asked by Abraham

A block and tackle having a velocity ratio of 5 is used to raise a load of 400N through a distance of 10m. If the workdone against friction is 100J. Calculate
1. Efficiency
2. The effort applied
Answered by Abraham
Am finding it difficult to answer.
Answered by R_scott
400 N * 10 m = 4 kJ ... work to raise the load ... output

a v.r. of 5 , means that the input line is pulled ... 5 * 10 m

the input work is ... 4 kJ + 100 J = 4.1 kJ

efficiency = output / input = 4 / 4.1

applied effort = 4.1 kJ / 50 m = ? N