Page 53 - Science Course 2 (Book 2)

Mo9-L2b: What are Complex Machines? Mo9-L2c: What is Mechanical Ef ciency?

When the input distance of a machine is larger than SUMMARY
the output distance, the output force is larger than What are Complex Machines?
the input force.
A bicycle is an example of a complex machine
Machines also can change the direction of a force. that is made up of different simple machines.

With incline
plane weight
effort needed
With incline = 10kg
plane weight
= 25kg

Mo9-L2c What is Mechanical Ef ciency?

KEY CONCEPTS:
The window washer’s pulley system makes the work 1. What is mechanical ef ciency?
of lifting easier.
Vocabulary A-Z

Let us learn some vocabulary

(mechanical) ef ciency

is the ratio of output work to input work.
Also known as mechanical advantage.

Key Concept

What are Complex Machines?
Let’s Begin
How can machines make work easier?

Ef ciency

(Mechanical) ef ciency (also known as mechanical
advantage) is the ratio of output work to input work.

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