Saved Bookmarks
| 1. |
The radius of our galaxy is about 3 xx 10 ^(20)m.With what speed should a person travel so that he can reach from the centre of the galaxy to its edge in 20 years of his lifetime ? |
|
Answer» SOLUTION :LET the speed of the person be v . As seen by the person, the edge of the galaxy is coming towards him at a speed v. In 20 years (as measured by the person ), the edge moves (20 y ) v and reaches the person. The radisu of the galaxy as measured by the person is , therefore , (20 y)v . The rest LENGTH of the radius of the galaxy is ` 3 xx 10^(20)m. ` Thus , ` (20y )v = (3 xx 10^(20)m) (sqrt 1 - v ^(2)/ c^(2) ` or, (6 .312 xx 10 ^(8) s ) ^(2) v^(2) = (9 xx 10 ^(40) m ^(2)) (1- v^(2) / c^(2) )`. Solving this, v =0.9999996 c. |
|