What is the overall efficiency of the compound machine if the - ProProfs Discuss

# What is the overall efficiency of the compound machine if the efficiency of the pulley is 90%? A compound machine used to raise heavy boxes consists of a ramp and a pulley. The efficiency of pulling a 100 kg box up the ramp is 50%.

A. 40%
B. 45%
C. 50%
D. 70%

This question is part of Physics Chapter 10 Energy, work, and simple machines
Asked by Yssacrekab, Last updated: Feb 16, 2020

#### W. Pratt

Want to learn new things and share my knowledge

W. Pratt, Marketing Analyst, MBA, Lincoln

Answered Apr 10, 2019

The correct answer to this question is B, 45%. This question would be asked on physics tests. The focus of this question is energy, work, and simple machines. In physics, energy is the capacity of doing work. There are various forms of energy including kinetic, thermal, and nuclear energy. Work is the action force completes and it moves energy.

Simple machines do work by using only one movement. Examples of simple machines include screws, wheels and axles, and wedges. These simple machines don't change the amount of work needed to do task, but they do change how work is done.

#### John Smith

John Smith

Answered Dec 20, 2016

45%

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