Extra Problems - Introduction

You will find the following numbers useful. The speed of light is 3x10⁵ km-sec^-1.

1 AU is 1.5x10⁸ km.

One year = about 3x10⁷ seconds.

1 light year is about 10¹³ km.

1. 10⁴x10⁶ = ?
2. 10⁴/10²=?
3. (10¹⁶)^1/2 = ?
4. 6x10²x3.5x10³ =?
5. (64x10⁸x36x10¹²)^1/2 = ?
6. How long does it take light to travel from the Sun to Jupiter? (Jupiter is roughly 5 AU from the Sun).
7. A radar pulse takes 2 hours to travel from Earth out to an asteroid and return. How far away is the asteroid?
8. Two galaxies are moving apart at 15,000 km/sec. If they are 6x10⁸ ly apart, how long ago did they begin moving apart (assume they separate at a constant speed). Note: Be sure not to mix light years and km as units here. Convert one to the other, it doesn't matter which.
9. In the previous problem, you got an answer in seconds. How many years is it?