1 For automobiles a taxpayer uses for business purposes, the portion of the business standard mileage rate treated as depreciation is 23 cents per mile for 2013, the same as in 2012. 2  The IRS also publishes a standard mileage rate for the use of a vehicle for medical or moving purposes.
What causes continuous rolling thunder when no lightning visible? Thunder is caused by the rapid expansion of super-heated air as electrical spark passes through. What causes the long (ie some several seconds) of rumbling when no lightning is visible even at night during tropical downpours?
When lightning strikes, it heats up the air a lot and causes it to expand with an explosive sound (thunder). EDIT: Ground shaking is an earthquake. Thunder accompanies thunderstorms, which have lightning. Thunderstorms are created by a cooler air mass colliding with a warm air mass, forcing the warm air mass up rapidly, decreasing pressure, temperature, and water saturation capacity, and creating lots of rain.