Saved Bookmarks
| 1. |
For what value of (a) are the vectors ltbRgt ` vec A= 2 a hat i-2 hat j + hat k` and ` vec B a hat I + a hat j -4 hat k` perpecdicular to each other ? |
|
Answer» If ` vec A ` is perpendicular to `brv B`, then vec A, vec B =0` ltbRgt ( 2 a hat i-2 aht j + ahtk).(a hat i+ a hat j- 4 hat k) =0` ltbRgt or` `2 a^2 -2 a - 4 =0 ` or `2 a^2 -4 a+ 2 a- 4 =0` or ` 2 a (a- 2) + 2 9a -2) =0` ltbRgt pr ` (2 a + 2) ( a-2) =0` If ` a- 2 =0` then ` a= 2` If ` 2 a = 2 =0` theta ` a=- 1`. |
|