# Light years

Not what you're looking for?

An astronomical unit of distance is the light-year, which is the distance light travels in one year. Compute this distance in meters. How many meters away is a star at a distance of 4 light-years from the earth?

##### Purchase this Solution

##### Solution Summary

This solution explains in 38 words how to calculate distance using speed of light and time.

##### Solution Preview

Solution.

The speed V of light is V=299792458 (m/second). The ...

###### Education

- BSc , Wuhan Univ. China
- MA, Shandong Univ.

###### Recent Feedback

- "Your solution, looks excellent. I recognize things from previous chapters. I have seen the standard deviation formula you used to get 5.154. I do understand the Central Limit Theorem needs the sample size (n) to be greater than 30, we have 100. I do understand the sample mean(s) of the population will follow a normal distribution, and that CLT states the sample mean of population is the population (mean), we have 143.74. But when and WHY do we use the standard deviation formula where you got 5.154. WHEN & Why use standard deviation of the sample mean. I don't understand, why don't we simply use the "100" I understand that standard deviation is the square root of variance. I do understand that the variance is the square of the differences of each sample data value minus the mean. But somehow, why not use 100, why use standard deviation of sample mean? Please help explain."
- "excellent work"
- "Thank you so much for all of your help!!! I will be posting another assignment. Please let me know (once posted), if the credits I'm offering is enough or you ! Thanks again!"
- "Thank you"
- "Thank you very much for your valuable time and assistance!"

##### Purchase this Solution

##### Free BrainMass Quizzes

##### Intro to the Physics Waves

Some short-answer questions involving the basic vocabulary of string, sound, and water waves.

##### Introduction to Nanotechnology/Nanomaterials

This quiz is for any area of science. Test yourself to see what knowledge of nanotechnology you have. This content will also make you familiar with basic concepts of nanotechnology.

##### Basic Physics

This quiz will test your knowledge about basic Physics.

##### Classical Mechanics

This quiz is designed to test and improve your knowledge on Classical Mechanics.

##### The Moon

Test your knowledge of moon phases and movement.