Class 9 Science | Efficiency

Science and Technology, Class 9

Efficiency

Unit 8 · Simple and complex machines · η = MA/VR × 100%

Today's Objectives

🔄

Give the reason the wheel and axle is a continuous lever

🏗️

Recognise complex machines as combinations of simple ones

⚖️

Tell output work and input work apart

📊

Calculate efficiency

⚡Multiplies speed

Load distance greater than effort distance

Thread winds fast onto a reel

Effort applied at the axle

💪Magnifies force

Effort distance greater than load distance

A steering wheel turns a heavy vehicle's wheels

A truck's wheel is bigger than a car's

The notes are free to read in full.

Presenter notes: Today we learn to measure how much of the work done on a machine is really useful. We begin from the wheel and axle.