A vector \({\vec{A}}\) is rotated by small angle \(\mathrm{\Delta}\mathrm{\theta}\) radians \(({\Delta}\theta<<1)\) to get a new vector \(\vec{B}.\) In that case \(|\vec{B}-\vec{A}|\) is: 
1. \(\vec{A}|\Delta \theta|\)
2. \(\mathrm{|\vec{B}| \Delta \theta-|\vec{A}|}\)
3. \(|\vec{\mathrm{A}}|\left(1-\frac{\Delta \theta^2}{2}\right)\)
4. \(0\)
Subtopic:  Resultant of Vectors |
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Let \(\vec{A}=(\hat{i}+\hat{j})\) and \(\vec{B}=(\hat{2} i-\hat{j}) .\) The magnitude of a coplanar vector \(\vec C \) such that \(\vec A.\vec C=\vec B.\vec C=\vec A.\vec B\) is given by:
1. \(\sqrt{\frac{9}{12}}\)
2. \(\sqrt{\frac{20}{9}}\)
3. \(\sqrt{\frac{5}{9}}\)
4. \(\sqrt{\frac{10}{9}}\)
Subtopic:  Vector Product |
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Let \(\left|\vec{A_1}\right|=3,\left|\vec{A_2}\right|=5\) and \(\left|\vec{A_1}+\vec{A_2}\right|=5.\) The value of \(\left(\vec{2 A_1}+3 \vec{A_2}\right) \cdot\left(3 \vec{A_1}-2 \vec{A_2}\right) \) is:

1. \(-112.5 \) 2. \(-106.5 \)
3. \(-118.5 \) 4. \(-99.5 \)
Subtopic:  Scalar Product |
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A balloon is rising vertically above a fixed point \(A\) on the ground. A girl at point \(B,\) located \(d\) metres from \(A,\) observes the balloon at a height \(h_1\)​ and sees it at an angle of \(45^\circ\) with respect to the vertical. After the balloon ascends an additional height \(h_2,\) the girl walks \(2.464d\) metres further away from point \(A\) to reach point \(C.\) From this new position, she observes the balloon at an angle of \(60^\circ\) with the vertical. If \(\tan 30^{\circ}=0.5774,\) then what is the value of \(h_2\)​ in terms of \(d \text{?}\)

             
1. \(d\)
2. \(0.732d \)
3. \(1.464 d \)
4. \(0.464 d \)

Subtopic:  Trigonometry |
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A particle moving in the xy plane experiences a velocity-dependent force \(\vec F= k\left(v_y\hat i +v_x \hat j\right)\) where \(v_x\) and \(v_y\) are the \(x\) and \(y\) components of its velocity \(\vec{v}\). If \(\vec{a}\) is the acceleration of the particle, then which of the following statements is true for the particle? 

1. Quantity \(\vec{v}.\vec{a}\) is constant in time. 
2. Kinetic energy of particle is constant in time. 
3. Quantity \(\vec{v}\times\vec{a}\) is constant in time. 
4. \(\vec{F}\) arises due to a magnetic field. 

Subtopic:  Vector Product |
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In a regular octagon \({ABCDEFGH},\) all sides are equal in length. The position vector of point \(A\) with respect to the center \(O\) of the octagon is given by: \(\overrightarrow{{AO}}=2 \hat{{i}}+3 \hat{{j}}-4 \hat{{k}}.\)
What is the value of the vector sum: \(\overrightarrow{{AB}}+\overrightarrow{{AC}}+\overrightarrow{{AD}}+\overrightarrow{{AE}}+\overrightarrow{{AF}}+\overrightarrow{{AG}}+\overrightarrow{{AH}} ~\text{?}\)

                     
1. \( -16 \hat{i}-24 \hat{j}+32 \hat{k} \)
2. \( 16 \hat{i}+24 \hat{j}-32 \hat{k} \)
3. \( 16 \hat{i}+24 \hat{j}+32 \hat{k} \)
4. \(16 \hat{i}-24 \hat{j}+32 \hat{k} \)

Subtopic:  Resultant of Vectors |
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If \(\vec{P} \times \vec{Q}=\vec{Q} \times \vec{P},\) the angle between \(\vec{P}\) and \(\vec{Q}\) is \(\theta\) \((0^\circ<\theta<360^\circ),\) then the value of \(\theta\) will be:
1. \(30^\circ\)
2. \(60^\circ\)
3. \(90^\circ\)
4. \(180^\circ\)

Subtopic:  Vector Product |
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\(\vec A\) is a vector quantity such that \(| \vec A|\) = non-zero constant. Which of the following expressions is true for \(\vec A\)
1. \(\overrightarrow{\mathrm{A}} \cdot \overrightarrow{\mathrm{A}}=0 \)
2. \(\overrightarrow{\mathrm{A}} \times \overrightarrow{\mathrm{A}}<0 \)
3. \(\overrightarrow{\mathrm{A}} \times \overrightarrow{\mathrm{A}}=0 \)
4. \(\overrightarrow{\mathrm{A}} \times \overrightarrow{\mathrm{A}}>0\)
Subtopic:  Scalar Product |
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Which of the following relations is true for two unit vectors \(\hat A\) and \(\hat B\) making an angle \(\theta\) to each other? 
1. \(|\hat{\mathrm{A}}+\hat{\mathrm{B}}|= |\hat{\mathrm{A}}-\hat{\mathrm{B}} \mid \tan \frac{\theta}{2} \)
2. \(|\hat{\mathrm{A}}-\hat{\mathrm{B}}|=|\hat{\mathrm{A}}+\hat{\mathrm{B}}| \tan \frac{\theta}{2} \)
3. \(|\hat{\mathrm{A}}+\hat{\mathrm{B}}|=|\hat{\mathrm{A}}-\hat{\mathrm{B}}| \cos \frac{\theta}{2} \)
4. \(|\hat{\mathrm{A}}-\hat{\mathrm{B}}|=|\hat{\mathrm{A}}+\hat{\mathrm{B}}| \cos \frac{\theta}{2}\)
Subtopic:  Resultant of Vectors |
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Two vectors \(\vec A \) and \(\vec B\) have equal magnitudes. If the magnitude of \(\vec A + \vec B\) is equal to two times the magnitude of \(\vec A - \vec B\), then the angle between \(\vec A \) and \(\vec B\) will be:
1. \(\sin ^{-1}\left(\frac{3}{5}\right) \)
2. \(\sin ^{-1}\left(\frac{1}{3}\right) \)
3. \(\cos ^{-1}\left(\frac{3}{5}\right) \)
4. \(\cos ^{-1}\left(\frac{1}{3}\right)\)
Subtopic:  Resultant of Vectors |
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