For a given level of technology, there is a maximum density of "bits" of information that can be stored on a computer's hard-drive disk. the data are stored in a tight spiral, so that "tracks" are essentially circles of increasing radius from inner to outer parts of the disk. as the disk spins at a constant rate, data are read at a constant rate regardless of the radius of the track being read.

Spend time observing or thinking about events that involve matter and energy. which events can you explain? which events can’t you explain?

Animals respond in various ways to stimuli detected through their senses. some of these responses are stimulated by the presence of danger. which of these animal responses is the best example of a response to an immediate threat? a) a rooster crows every morning at the first sign of light. b) as something approaches an octopus, it shoots a cloud of ink. c) from late fall until spring, bears hibernate to preserve energy. reactivate d) a dog is getting hot in the sunlight, so he moves to a shaded area.

How is coal extracted from mountaintop removal mines? a. dynamite is used to create underground tunnels where miners go to extract the coal. b. dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal. c. coal in mountaintops is extracted by digging strips in the landscape to reach the coal. d. placer deposits in mountain river bottoms are removed by