Questions

Mercator projection type of maps are best suited for maritime navigations.

A dynamometer wattmeter can be used for measuring both A.C and D.C currents.

Headache and Heartache are the only two words that of more than 2 letters that both begins and ends with the letters "HE" in the same order.

Coal is chemically complex fuel. Whenever it is burned, gases are given off and particles of ash, called "fly ash," are released. Release of sulfur from burning into the air. The sulfur in coal combines with oxygen to form sulfur dioxide, which can be a major source of air pollution if emitted in large enough quantities. This stuff comes back as acid rain when it attaches itself to a raindrop. 

Today, many of the effects of coal burning have been reduced significantly or eliminated. This is super-nasty and is only stopped by buying low-sulfur coal from Montana or Wyoming. The eastern power plants have to pay to move the coal from out west and this increases the price of power production.