fan and medal!
PArt A: the sun produces 3.9-10^33 ergs of radiant energy per second. how many ergs of radiant energy does the sun produce in 2.45 - 10^5 seconds?
PArt B: which is the more reasonable MEASUREMENT OF THE DISTANCE BETWEEN THE TRACKS on a DVD: 7.4-10^-4mm or 7.4-10^4mm?

Question

fan and medal!
PArt A: the sun produces 3.9-10^33 ergs of radiant energy per second. how many ergs of radiant energy does the sun produce in 2.45 - 10^5 seconds?
PArt B: which is the more reasonable MEASUREMENT OF THE DISTANCE BETWEEN THE TRACKS on a DVD: 7.4-10^-4mm or 7.4-10^4mm?

anonymous · Answer

Well if you've got 3.9x10^33 erg per second and 2.45x10^5 seconds, then you just multiply the two numbers together to get the total amount of radiant energy.

For the second bit, 7.4x10^-4mm is a very very small distance, and 7.4x10^4mm is 74 metres... can you guess which one is the right answer? :P

anonymous · Answer

ok um for the first part don't I add them instead?

anonymous · Answer

Nope. As a simpler example, say you have a car travelling at 10 metres per second, and it travels for 5 seconds. How far does the car travel? 5 x 10 = 50 metres. It's the same principle with this question.

anonymous · Answer

oh ok thanks! :)

anonymous · Answer

No problem :P