Outer space is often described as a vacuum, but there is always some matter present. In the space 400 km above Earth's surface, there is as little as 1.58 x 10-14 g of matter in a 500.0 cm3 volume of space. Based on this data, what is the density of the matter in space?

Car batteries are often rated in amp-hours. this rating indicates the quantity of charge that can pass through the battery before the battery's chemical energy must be restored by the car's generator or some other source. the amp-hour unit is convenient for simple calculations. for example, a 60-amp-hour battery can supply a current of 1.0 a for 60 h (or 60 a for 1.0 h) before going dead. find the energy stored in the following. (a) a 58 a-h, 10 v car battery(b) a 1.3 a-h, 1.7 v flashlight battery