20 POINTS NEED THIS ASAP Can you have a negative velocity? For example, can you go -15 kilometer per hour west? What would that mean?

What is the temperature in degrees celsius of a substance with a tempature of 49k

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.

Consider a file currently consisting of 200 blocks. assume that the file control block (and the index block in the case of indexed allocation) is already in memory. calculate how many disk i/o operations are required for contiguous, linked, and indexed (single-level) allocation strategies, for each of the conditions listed below. in the contiguous-allocation case, assume that there is not room to grow at the beginning but there is room to grow at the end. also assume that the block information to be added is stored in memory.