There are a few threads about timedelta, which should be helpful. But in short:
timedelta is the time that has passed between the last tick and the current one.
5e-002 means 0.05
That means, that your game's speed was 20 fps at that moment.
timedelta is always relative to the current framerate. If at times the processor doesn't have much to do and the framerate is e.g. 500 fps, then timedelta will be 0.002, at other times, when the framerate is only 10 fps, timedelta will be 0.1
Timedelta assures to do something over time, if (and only if) used on every tick.
If you do something like "a = a + 10 * timedelta", then a will raise by 10 per second, no matter the frame rate. But it does not evenly raise "a" per tick. It's just the opposite: it raises by whatever value is needed to get to a total of 10 per second, which may be a lower portion or a higher one, depending on the actual time, that passed between any two ticks.