QJEEM21Maa9e0: JEE Main 2021 Physics - Class 11 JEEM21Maa9e0 Solution: In a triangle ABC, if

Question

Verified Solution • 2025–26 Session moderate

In a triangle ABC, if

| \vec{B C} | = 3

,

| \vec{C A} | = 5

and

| \vec{B A} | = 7

, then the projection of the vector

\vec{B A}

on

\vec{B C}

is equal to :

Accepted Answer

Projection of

\vec{B A}

on

\vec{B C}

is equal to

= | \vec{B A} | \cos ∠ A B C

= 7 | \frac{7^{2} + 3^{2} - 5^{2}}{2 \times 7 \times 3} | = \frac{11}{2}

Step-by-Step Verified Solution