00:01
So this question is about some twins that travel on spaceships.
00:07
So there's a planet.
00:10
So here's the earth.
00:13
And there's a planet.
00:15
And the distance is 12 light years.
00:21
So one twin.
00:24
So if we think about distance, we've got the planet at 12 light years and the earth at zero light years.
00:33
And then we've got time here.
00:35
So one twin travels at a speed of night.
00:38
0 .9c reaches the planet and then waits for the second twin.
00:48
The second twin travels at 0 .5c, reaches the planet and intersects with the first twin.
00:59
And we're asked to calculate what is the difference between their ages when they meet? so what's going to be the difference between their ages at this point? so let's think about what these times are.
01:15
So this twin travels at half the speed of light, so this will be 24 years down the line.
01:23
This twin travels at 0 .9 times the speed of light, so the answer is going to be 12 divided by 0 .9, which is 13 .33 years...