Question

Given that A + B = R and A = B = R. What should be the angle between A and B?(a) 0 (b) π/3(c) 2π/3 (d) π

Answer 1

2π/3 is the correct answer to the question.

Answer 2

Answer:

Explanation:

Equation 1 - A + B = R (Given)

Equation 2 - A = B = R(Given)

Using the formula for the magnitude of resultant vector -

R = √(A²+B²+2ABcosΘ)

R² =A²+B²+2ABcosΘ  

As R=A=B

= R² = R²+R²+2R²cosΘ  

= R² = 2R²(1+cosΘ)  

= 1/2-1 =cosΘ  

cosΘ=-1/2  

Θ =120°  

Thus the resultant angle between the vector A and B will be 120°.