# word problem

• Mar 15th 2009, 02:14 PM
math1645
word problem
the speed of light is 1.863 x 10^5 miles per second.

assume 1 year is 365 days. write an expression to convert speed of light from miles per second to miles per year

make a table that shows the distance light travels in 1, 10, 100, 1000, 10000, 100000 years. our galazy has a diameter of about 5.875 x 10^17 miles. based on the tablem about how long would it take for light to travel across our galaxy.

i have no idea what to do. help
• Mar 15th 2009, 04:48 PM
marv88harrison
Quote:

Originally Posted by math1645
the speed of light is 1.863 x 10^5 miles per second.

assume 1 year is 365 days. write an expression to convert speed of light from miles per second to miles per year

make a table that shows the distance light travels in 1, 10, 100, 1000, 10000, 100000 years. our galazy has a diameter of about 5.875 x 10^17 miles. based on the tablem about how long would it take for light to travel across our galaxy.

i have no idea what to do. help

(1.863 * 10^5 miles / sec) * (60 sec / minute) * (60 minutes / hour) * (24 hours / day) * (365 days / year)

Cancel out units.
5.795 * 10^12 miles / year

Create a table by multiplying years by the expression above
Years Miles
1___________5.795 * 10^12
10__________5.795 * 10^13
100_________5.795 * 10^14
1000________5.795 * 10^15
10000_______5.795 * 10^16
100000______5.795 * 10^17

With a diameter of about 5.875 x 10^17 miles and based on the table it would take light 100000 years to travel across our galaxy