Question

2. As you stand in your backyard on a clear night, an alien spacecraft flies overhead with a speed of 0.600c from a great distance. The alien pilot on the spacecraft turns on his searchlights for 1.00 x 10-3 s as measured by him (a) How long was the searchlight of the spacecraft on as measured by you? (b) In the time that the searchlight was on, how far did the spacecraft travel as measured by you? (c) In the time that his searchlight was on, how far did the spacecraft travel as measured by the alien pilot?

Answer 1

(a) The time interval $\Delta t_{o}$ passed in spaceship is observed as $\Delta t_{}$ in the your frame of reference, which is in relative motion with the spaceship

3 I- U2 2.

(b) Distance travelled by the spaceship in your frame of reference is

$s = v\Delta t_{} = 0.6c \times 1.25\times10^{-3} = 225km$

(c) In spaceship's frame the Distance traveled is

$s_{o} = v\Delta t_{o} = 0.6c \times 1\times10^{-3} = 180km$