Question

3. The position vectors of radius are 21+i+k and 2i+3j+k while those of linear momentum are
3-31- Then the angular momentum is
2-4 (B) 4i-8k (C) 2-4j+(D) 4-8​

Answer 1

Given: The correct position vectors of radius are  2i+j+k and 2i+3j+k while those of linear momentum are 2i+3j-k.

To find: The angular momentum?

Solution:

• So now, we know that angular momentum has the formula of:

                L = r x P

• So now putting the given vectors in formula we get:

                { ( 2i + 3j + k ) − ( 2i + j + k) } x ( 2i + 3j - k )

                ( 0i + 2j + 0k ) x ( 2i + 3j - k )

                det of $\left[\begin{array}{ccc}i&j&k\\0&2&0\\2&3&-1\end{array}\right]$

                = -2i - 4k

Answer:

           The angular momentum vector is -2i - 4k.