00:01
Hello students, in the first part of the question, the question is minus 4a plus 3b plus 5c.
00:09
The vectors a, b and c are given in the question.
00:13
So on finding out this, we can substitute those values as minus 4 into a is given as 3i minus 2j plus 4k plus 3 into b vector is given as 6i plus 2j minus 5k plus 5 into c vector is minus 9i plus 8j plus 7k.
00:43
So here we will get the answer that is a resultant vector as minus 39i plus 54j plus 14k.
00:55
Now let's find out the magnitude of the resulting vector which will be equal to whole root of minus 39 square plus 54 square plus 14 square.
01:13
So we will get the magnitude of r as 68 .09 newton.
01:19
Now for the second question, let's find out 5a plus 5b plus 9c first.
01:29
Therefore, the resultant vector will be equal to 5 into the a vector is 3i minus 3j plus 7k plus 5 into 9i plus 9j minus 8k plus 9 into minus 8i plus 4j plus 3k.
01:53
So finding out the resultant vector, we will get the answer as minus 12i plus 66j plus 22k.
02:04
Now let's find out the theta value that is we know that tan theta x is equal to the components of the resultant vector along the x -axis divided by the components of the resultant vectors along the y -axis.
02:29
So the components will be that is theta x will be equal to tan inverse of minus 12 by the y component is 66.
02:41
So here we will get the theta value as minus 10 .11 degree...