Nanoseconds and Time for Light to Travel

[Dsingh]

Homework Statement

The problem asks how many nanoseconds does it take for light to travel 1km in a vacuu?

Homework Equations

I know that 1KM is equal to 1000 meters or 10^3. I also know that 1ns is equal to 10^-9s and light travels at about .3m per ns.

The Attempt at a Solution

I'm not sure where to start with this problem. I know I have to convert the two givens but I am stuck at where to start. I started to think that I could divide the .3m per ns by 10^9 and then multiply it by 10^3. If someone could help me figure out how to start this problem and a push in the right direction that would be highly appreciated. Thanx in advanced.

 

[Galileo]

You probably remember:
distance = velocity x time

so

time = distance/velocity.

for constant velocity. So use that.
You can always get the right relation by considering the units on both sides if you don't see it right away.

 

[m2003]

First, we need to understand the units involved in this problem. We are given a distance of 1km, which is equal to 1000 meters. We also know that 1 nanosecond (ns) is equal to 10^-9 seconds (s). Finally, we are told that light travels at a speed of approximately 0.3 meters per nanosecond.

To solve this problem, we need to use the formula: time = distance/speed. In this case, we are looking for the time it takes for light to travel 1km, so our distance is 1000 meters and our speed is 0.3 meters per nanosecond.

Plugging these values into the formula, we get:

time = 1000 meters / 0.3 meters per ns = 3333.33 ns

Therefore, it takes approximately 3333.33 nanoseconds for light to travel 1km in a vacuum.