A particle moves from a point $(-2\hat{\mathrm{i}}+5\hat{\mathrm{j}})$ to $(4\hat{\mathrm{j}}+3\hat{\mathrm{k}})$ when a force of $(4\hat{\mathrm{i}}+3\hat{\mathrm{j}}) N$ is applied. How much work has been done by the force?

1.  8 J

2.  11 J

3.  5 J

4.  2 J

If vectors $\overrightarrow{\mathrm{A}}=\mathrm{cos\omega t}\hat{\mathrm{i}}+\mathrm{sin\omega t}\hat{\mathrm{j}}$ and $\overrightarrow{\mathrm{B}}=\cos \frac{\mathrm{\omega t}}{2}\hat{\mathrm{i}}+\sin \frac{\mathrm{\omega t}}{2}\hat{\mathrm{j}}$ are functions of time. Then, at what value of t are they orthogonal to one another?

1. $\mathrm{t}=\frac{\mathrm{\pi }}{4\mathrm{\omega }}$

2. $\mathrm{t}=\frac{\mathrm{\pi }}{2\mathrm{\omega }}$

3. $\mathrm{t}=\frac{\mathrm{\pi }}{\mathrm{\omega }}$

4. $\mathrm{t}=0$

$\overrightarrow{\mathrm{A}}$ and $\overrightarrow{\mathrm{B}}$ are two vectors and θ is the angle between them. If $\left|\overrightarrow{\mathrm{A}}\times \overrightarrow{\mathrm{B}}\right|=\sqrt{3}\left(\overrightarrow{A}.\overrightarrow{B}\right)$, then the value of θ will be:

1. 60^o

2. 45^o

3. 30^o

4. 90^o

If a vector ($2\hat{\mathrm{i}}+3\hat{j}+8\hat{k}$) is perpendicular to the vector ($4\hat{\mathrm{i}}-4\hat{j}+\mathrm{\alpha }\hat{k}$), then the value of $\mathrm{\alpha \; is}$

1. -1

2. $-\frac{1}{2}$

3. $\frac{1}{2}$

4. 1

If the angle between the vector $\overrightarrow{\mathrm{A}}\text{ and }\overrightarrow{\mathrm{B}}$ is θ, the value of the product $(\overrightarrow{\mathrm{B}}\times \overrightarrow{\mathrm{A}})\cdot \overrightarrow{\mathrm{A}}$ is equal to

1. zero

2. BA²sinθcosθ

3. BA²cosθ

4. BA²sinθ

$\begin{array}{l}\text{ If }|\overrightarrow{\mathrm{A}}\times \overrightarrow{\mathrm{B}}|=\sqrt{3}\overrightarrow{\mathrm{A}}\cdot \overrightarrow{\mathrm{B}}\text{, then the value of }\\ |\overrightarrow{\mathrm{A}}+\overrightarrow{\mathrm{B}}|\text{ is: }\end{array}$

1. ${({\mathrm{A}}^2+{\mathrm{B}}^2+\frac{\mathrm{AB}}{\sqrt{3}})}^{1/2}$

2. A+B

3. ${({\mathrm{A}}^2+{\mathrm{B}}^2+\sqrt{3}\mathrm{AB})}^{1/2}$

4. ${({\mathrm{A}}^2+{\mathrm{B}}^2+\mathrm{AB})}^{1/2}$