Solve this:
Q). State the triangle law of vector addition and derive the expression to find the magnitude of resultant of two vectors of magnitude , inclined at an angle .
So, we have
R = P + Q
Now, expand A to C and draw BC perpendicular to OC.
From triangle OCB,
In triangle ACB,
Also,
Magnitude of resultant:
Substituting value of AC and BC in (i), we get
which is the magnitude of resultant.
Let ø be the angle made by resultant R with P. Then,
From triangle OBC,
which is the direction of resultant.