assignment01s

# assignment01s - Assignment 1 Due Sept 16 1 Communication...

This preview shows pages 1–2. Sign up to view the full content.

Assignment 1 Due Sept. 16 1. Communication with mars. We use radiowaves, which travel at the speed of light, to communicate with robotic spacecraft. How long does it take a message to travel from Earth to a spacecraft on Mars when: a. Mars is as it closest to Earth? b. Mars is at its farthest from Earth? (Data: The distance from Earth to Mars ranges between about 56 and 400 million kilometers.) Solution: We will use the speed-time-distance relationship: Time of travel = distance traveled / speed The speed of light = 3 x 10 5 km/s; a. Mars as its nearest is 56 million kilometers away, so the light travel time is: time of travel = 5.6 x 10 7 km / (3x10 5 km/s) = 187 s b. At the most distant, Mars is 400 million kilometers from Earth, time of travel = 4 x 108 km / (3x10 5 km/s) = 1330 s 2. Galaxy Scale. Consider the 1-to-10 19 scale on which the disk of the Milk Way Galaxy fits on a football field. On this scale, how far is it from the Sun to Alpha Centauri (real distance: 4.4 light-years)? How big is the Sun itself on this scale? Compare the Sun’s size on this scale to the size of a typical atom (real diameter: about 10

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 10/01/2008 for the course PHYS 185 taught by Professor Mei,d during the Fall '08 term at University of South Dakota.

### Page1 / 3

assignment01s - Assignment 1 Due Sept 16 1 Communication...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online