Answer to Question #287645 in Mechanics | Relativity for prabhat

Question

Find the sum of A = 3i + 4j -5K and B = -i + 2j +6z

Answer 1

Explanation & Calculation

• All the quantities are given in vector form so that it is just the addition of the coefficients of each unit vector to get the sum of them.

$\qquad\qquad \begin{aligned} \small \Sigma&=\small 3 \underline {i}+4\underline{j}-5\underline{k}+(-\underline{i}+2\underline{j}+6\underline{k})\\ &=\small (3-1)\underline{i}+(4+2)\underline{j}+(-5+6)\underline{k}\\ &=\small 2\underline{i}+6\underline{j}+\underline{k} \end{aligned}$

• There should be a mistake in the second vector with its last unit vector. Unless the z is defined there is no meaning to the question.