Man's Way of Helping Himself:
Out of the few simple machines mentioned in the preceding Sections has developed the complex machinery of to-day. By a combination of screw and lever, for example, we obtain the advantage due to each device, and some compound machines have been made which combine all the various kinds of simple machines, and in this way multiply their mechanical advantage many fold.
A relatively simple complex machine called the crane maybe seen almost any day on the street, or wherever heavy weights are being lifted. It is clear that a force applied to turn wheel 1 causes a slower rotation of wheel 3, and a still slower rotation of wheel 4, but as 4 rotates it winds up a chain and slowly raises Q. A very complex machine is that seen in Figure .
FIG. - A simple derrick for raising weights.
FIG. - A traveling crane.
FIG. - A farm engine putting in a crop.
How to Prepare Oxygen
Journeys Made by Molecules
Value of Fire
The Window Pane
How to produce Rainbow Colors
Care of the Ear
The Human Eye
Good and Bad Mirrors
Test your English Language
Rules to play Underwater Photography
Rules to play Water Skiing
Rules to play Weightlifting
Rules to play Wheelchair Basketball
Rules to play Wheelchair Tennis
Rules to play Yo Yo
Rules to play Yoga
Saffron Or Kesar Get Beautiful Skin
Benefits of Fennel Seeds
Smartest People Of All Time
Mountain Ranges You Need To Visit
Foods to help you win the war on Weight
Rules to play Bobsleigh
Benefits of Endives
Unhealthy Habits That Will Cost You Dearly
Most Beautiful Mosques In The World
Benefits of Elderberry
Most Extensive Metro Systems In The World