Question

a light year is 9.5*10^12 km. the diameter of the milky way galaxy is estimated to be 100,000 light years.

A) what is the diameter of the milky way im kilometers?
B) the speed of light is about 3*10^8 m/s. what is the speed of light in kilometers per hour?
C) about how many days would it take light to travel across the milky way?
D) about how many years would it take light to travel across the milky way?

Answer 1

100,000 = 1 * 10^5 lighyears

Answer 2

so A is 1 * 10^5 * 9.5 * 10^12

Answer 3

thats 9.5*10^17 right? @welshfella

Answer 4

yea

Answer 5

for B you need to use the 2 conversion factors 1 km = 1000m and 1 hr = 3600 secinds

Answer 6

ok

Answer 7

so what do i do? @welshfella

Answer 8

to find meters per hour you multiply by 3600
then to find km / hr you divide the result by 1000

Answer 9

what do i multiply?

Answer 10

the answer to the last one? @welshfella

Answer 11

no wait i multiply it by the thing in the top right? @welshfella

Answer 12

no speed of light 3 * 10^8

multiply this by 3.6 * 10^3

then divide the result by 10^3

Answer 13

ok i got 1080000 @welshfella