Physics repost

posted by .

I apologise for reposting this question but it is still not working out for me.

I know that:

speed of light c=3.0x10^8
Time interval delta t=0.19x10^-9s

The relationship between actual time and roudtrip distance is

d=ct

Also if there is and uncertainty of delta time, then it introduces an uncertainty of delta distance

ie d+delta d = c(t + delta t)

Knowing all of this I still don't understand how to work out the problem. I am continuosly coming up with the incorrect answer. please help!

Question:
The distance between earth and the moon can be determined from the time it takes for a laser beam to travel from earth to a reflector on the moon and back. If the round-trip time can be measured to an accuracy of 0.19 of a nanosecond (1 ns = 10-9 s), what is the corresponding error in the earth-moon distance?

  • Physics repost -

    The Earth moon distance is d, and the round-trip travel time is
    t = 2 d/ c
    d = (c/2) t

    delta d = 1.5*10^8 m/s * (delta t)
    = 0.19*10^-9 s *(1.5*10^8 m/s) = 2.9*10^-2 m = 2.9 cm
    (about one inch)

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Class 11th Physics

    My question is that, I read about Instantaneous Speed "Instantaneous speed of an object at an instant of time (t) is defined as the 'limit of the average speed as the time interval delta(t) at the given instant of time becomes infinitesimally …
  2. general physics

    We can interpret a distance traveled of 7.43 to mean a distance between 7.425 and 7.435 , thus rounding to 7.43 . Similarly, a time interval of 0.83 implies a time interval between 0.825 and 0.835 . Use these values to justify the …
  3. rate of reaction (formatted repost)

    I can't get my table to line up so I've surrounded the values in curly brackets. Experiment [SO2]i [O2]i IRD O2 {1} {0.05} {0.05} {7.3*[10^(-2)]} {2} {0.10} {0.05} {2.9*[10^(-2)]} {3} {0.10} {0.15} {2.6*[10^(-1)]} {4} {0.12} {0.12} …
  4. Physics

    These are “plug-in-the-number” tasks to familiarize you with the main formulas that link the physics concepts of this chapter. They are one-step substitutions, much less challenging than the Think and Solve problems that follow. …
  5. Physics,Question ,Solved but about Units?

    These are “plug-in-the-number” tasks to familiarize you with the main formulas that link the physics concepts of this chapter. They are one-step substitutions, much less challenging than the Think and Solve problems that follow. …
  6. physics

    Question: 15 of 30: The distance versus time plot for a particular object shows a quadratic relationship. Which column of distance data is possible for this situation?
  7. Physics

    Suppose the observed motion of a moving airplane, illustrated by a distance vs. time graph, is nearly a straight line with zero distance traveled at zero time. State what this shows about the relationship between distance and time, …
  8. chemistry -repost

    Still can't figure this one out-- sorry for reposting, this is the last post, if someone has time to review this question and see if they can figure out how the textbook got 1.0x10^-7 seconds Iodine combines to form I2 in liquid propane …
  9. physics As

    The table below shows how the braking distance x for a car depends on its initial speed u u / ms-1 5.0 10 20 4 x / m 2.0 8.0 32 128 the reaction time of a driver is 0.60s. Calculate the sopping distance of the car when u= 30ms-1. The …
  10. Physics

    Q11.The table below shows how the braking distance x for a car depends on its initial speed u. | u / ms-1 | 5 | 10 | 20 | 40 | | X / M | 2 | 8 | 32 | 128 | The relationship between x and u is: doubling speed increases distance by a …

More Similar Questions