Flashing light beacon from Earth reaching spaceship moving away at 0.75c

[neelbansal123]

Homework Statement

You are on a spacecraft traveling away from the earth at 0.75 c. A beacon on earth flashes exactly once per second.

From the point of view of a person on earth, what is the time between one flash reaching your ship and the next?
Answer- 4 seconds
From your point of view, what is the time between one flash reaching your ship and the next?
Answer 2.6 seconds

No matter how I solve it I do not get the answers mastering physics says are correct. Any ideas?

Relevant Equations

Speed of light constant 3x10^8

Below

 

[erobz]

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[neelbansal123]

 

[neelbansal123]

 

[Hill]

View attachment 343142

Part A asks about the earth time of the flashes reaching your ship.
You don't need relativity to answer it. Just kinematics.

 

[BvU]

You don't need relativity to answer it. Just kinematics.

What might help is a diagram (see Minkowski diagram) like this:

(everything in seconds):
Flash emitted at earth t=0 has $x = ct$,
Flash emitted at earth t=1 reaches ship at t=4,
Flash emitted at earth t=2 arrives at t=8 etc.

$\$