How Does A Speedometer Work?

 Speedometer

 

A spinning magnet in a speedometer acts with magnetic force that pulls the pointer and causes it to register the auto’s speed.The speedometer in an automobile tells how fast the car is going.

A speedometer operates by magnetic force.  Inside a speedometer there is a magnet that is connected directly to the car’s transmission by a flexible cable.

When the car moves, gears inside the transmission turn the cable which spins the magnet.

Fitting over the magnet is a special metal drum called a “speedup.”  The speedup is attached to the pointer in the speedometer’s dial.

The spinning magnet acts with magnetic force that pulls the speed cup and it causes the pointer to revolve against the restraint of a spring.

When the car speeds up, the faster the magnet spins and the greater is the force exerted against the spring.

At the magnetic pull gradually overcomes the resistance of the spring, it causes the speedometer to register a higher speed.

When the car stops, the spring pulls the pointer back to zero. – Dick Rogers

Who invented barbed wire?

Barbed Wire

Barbed wire was invented by an American, Joseph F. Gidden, who patented it in 1874.

If you have over visited the countryside where livestock is raised, you probably know what barbed wire is.

Barbed wire is a cable of twisted wire armed with barbs of sharp points.  It is used particularly as an economic means of fencing off large areas.

It provided an inexpensive substitute for wood fences and enabled small farmers to fence in homesteads and settle communities on the western frontier.

Barbed wire is made by feeding two strands of wire, side-by-side, into the wire making machine.  Other wires used to make the barbs are run crosswise over the strand wires.  

At regular space intervals the machine cuts a length from them and twists the barbs around one or both strand wires.  After this is done, the strand wires are twisted together to form the finished cable.  It is then rolled to shipment to dealers.-Dick Rogers