Question

Three coplanar vectors A,B and C have magnitudes 4,3&2 respectively.If the angle between any two vectors is 120 degrees,then which of the following vectors may be equal to 3Avector/4+Bvector/3+Cvector/2

Answer 1

Answer:

Use this formula two times

After A- new vector

Answer 2

3|A|→/4 +  |B|→/3 + |C|→/2 = 2|A|→/4

Explanation:

Given:

|A|→ = 4

|B|→ = 3

|C|→ = 2

Find: If the angle between any two vectors is 120 degrees,then which of the following vectors may be equal to 3Avector/4+Bvector/3+Cvector/2

Solution:

3/4 *|A|→ = 3/4 * 4 = 3

|B|→/3 = 3/3 = 1

|C|→/2 = 2/2 = 1

 |A|→/4 + |B|→/3 +  |C|→/2 = 0 as the 3 vectors are 120 degrees between each other.

So 3|A|→/4 = 2|A|→/4  = |A|→/4

Hence 3|A|→/4 +  |B|→/3 + |C|→/2 = 2|A|→/4 in the direction of A→.