00:01
So question a asked for the time it took to travel from earth to a certain star by a spacecraft with a speed of 0 .95c, which is a speed of light, measured by the observers on earth.
00:23
So that given distance of the star from the earth is the rest length, which is 18 .6 light years.
00:37
And the formula for speed, we know that it is distance over time.
00:42
So time is equals to distance over the speed.
00:45
So we have 18 .6 light years over the speed, which is 0 .95c.
00:53
And we know that one light year per c is just one year.
01:01
So this equals to 19 .6 years.
01:14
So question b asked, for the time we travel to each start from our measure by the observers on the spacecraft.
01:22
So they experience time deletion.
01:24
So we will use time deletion formula here, where the deleted time is equal to the stationary time, which is the time we calculated from part a, multiplied by its factor...