Question

Two vectors have magnitudes 3 and 5. If angle between them is 60${}^{\circ }$, then the dot product of two vectors will be

• A. 7.5
• B. 6.5
• C. 8.4
• D. 7.9

Answer 1

Answer: (A)

Given A = 3. B = 5 and $\theta$ = 60${}^{\circ }$
$A.B=3\times 5\times cos60^{\circ }$
$A.B=15\times \frac{1}{2}=7.5$