Time for light to travel from tail to nose of moving spacecraft

[seto6]

Homework Statement

question

Solution

Homework Equations

given in the problem

The Attempt at a Solution

i did the question exactly like how they did it. expect i did not add the length contraction of 923m to 1000m, then find time.. what i did was find the speed with respect to me which was 0.385c
so d=vt t =d/v= 8.8*10^-6 s

can some one tell me where i went wrong.pls.

thanks in advance

 

[Doc Al]

i did the question exactly like how they did it. expect i did not add the length contraction of 923m to 1000m, then find time.. what i did was find the speed with respect to me which was 0.385c
so d=vt t =d/v= 8.8*10^-6 s

You used the wrong distance. You found the time for the nose of Orion to go from the tail to the nose of Sirius, but that's not the same as for Orion to completely pass. Draw a diagram for yourself (or just study the one given).

 

[seto6]

oh i see i got it thanks Doc