Magnitude of vector which comes on addition of two vectors,6i+7j and 3i+4j is

Vectors mcqs solution  Physics class 11 mcqs  First year physics mcqs

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00:00The question is magnitude of vector which comes on addition of two vectors 6i plus 7j

00:14and 3i plus 4j is a under root 136, b under root 13.2, c under root 202, d under root

00:27160. Else we have to find the magnitude of the resultant. Take a suppose A vector is

00:43obtained as 6i plus 7j and b vector is obtained as 3i plus 4j. So we have to find the magnitude

01:08of resultant. First of all we will find resultant. So resultant will be equal to A plus B. So

01:23resultant will be obtained as the value of A is 6i plus 7j plus the value of B is 3i

01:39plus 4j. So the resultant will be obtained as 6i plus 3i it will be 9i plus 7j plus 4j it will be 11j.

01:57Now we will find the magnitude of resultant means mod of R or we can also write it as R which is

02:08equal to under root x square plus y square because here two x's are given. So the magnitude of

02:23resultant will be obtained as under root square on x so the value of x is 9 because on x-axis

02:36we take i unit vectors and along y-axis we take j unit vector. So the square of x means 9 square

02:47plus y square means 11 square. So the magnitude of resultants will be R will be equal to under

03:04root the square of 9 is 81 plus the square of 11 is 121. So the magnitude of resultant will be

03:15obtained as 202. So the correct option will be C under root 202.