Review the solved problems below to understand question phrasing, answer choices, and step-by-step solution logic prior to starting the full interactive practice drill:
Sample Question 1
Exercise 7.1 - Vector Graphical Representation
MEDIUM • Short Question
Draw and represent the following vectors geometrically with appropriate scale and direction:<br>(i) $10\text{ N}$ force along the positive x-axis<br>(ii) $50\text{ m/s}$ velocity at $150^\circ$ with the positive x-axis<br>(iii) $220\text{ m}$ displacement towards North<br>(iv) $24\text{ m/s}^2$ acceleration at $45^\circ$ with the positive x-axis.
✓ Correct Answer: (i) 10i N, (ii) -25√3 i + 25j m/s, (iii) 220j m, (iv) 12√2 i + 12√2 j m/s²
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Geometrical Construction & Resolution:</strong><br><strong>(i) $10\text{ N}$ force along positive x-axis:</strong><br>• <em>Scale:</em> Let $1\text{ cm} = 2\text{ N} \implies \text{Length} = \frac{10}{2} = 5\text{ cm}$.<br>• <em>Direction:</em> Directed along positive x-axis (Angle $\theta = 0^\circ$).<br>• <em>Component Form:</em> $\vec{F} = [10\cos 0^\circ, 10\sin 0^\circ] = [10, 0] = 10\hat{i}\text{ N}$.<br><br><strong>(ii) $50\text{ m/s}$ velocity at $150^\circ$ with positive x-axis:</strong><br>• <em>Scale:</em> Let $1\text{ cm} = 10\text{ m/s} \implies \text{Length} = \frac{50}{10} = 5\text{ cm}$.<br>• <em>Direction:</em> In Quadrant II at $\theta = 150^\circ$.<br>• <em>Component Form:</em> $\vec{v} = [50\cos 150^\circ, 50\sin 150^\circ] = [50(-\frac{\sqrt{3}}{2}), 50(\frac{1}{2})] = [-25\sqrt{3}, 25] \approx [-43.3, 25]\text{ m/s} = -25\sqrt{3}\hat{i} + 25\hat{j}\text{ m/s}$.<br><br><strong>(iii) $220\text{ m}$ displacement towards North:</strong><br>• <em>Scale:</em> Let $1\text{ cm} = 50\text{ m} \implies \text{Length} = \frac{220}{50} = 4.4\text{ cm}$.<br>• <em>Direction:</em> Due North corresponds to positive y-axis (Angle $\theta = 90^\circ$).<br>• <em>Component Form:</em> $\vec{d} = [0, 220] = 220\hat{j}\text{ m}$.<br><br><strong>(iv) $24\text{ m/s}^2$ acceleration at $45^\circ$ with positive x-axis:</strong><br>• <em>Scale:</em> Let $1\text{ cm} = 6\text{ m/s}^2 \implies \text{Length} = \frac{24}{6} = 4\text{ cm}$.<br>• <em>Direction:</em> In Quadrant I making an angle of $45^\circ$ with the horizontal.<br>• <em>Component Form:</em> $\vec{a} = [24\cos 45^\circ, 24\sin 45^\circ] = [24(\frac{1}{\sqrt{2}}), 24(\frac{1}{\sqrt{2}})] = [12\sqrt{2}, 12\sqrt{2}] \approx [16.97, 16.97]\text{ m/s}^2 = 12\sqrt{2}\hat{i} + 12\sqrt{2}\hat{j}\text{ m/s}^2$.
Sample Question 2
Exercise 7.1 - Scalar Multiples of Vectors
MEDIUM • Short Question
Given vector $\vec{F}$ is $4\text{ cm}$ long making an angle of $45^\circ$ with the positive x-axis. Find the length and orientation of:<br>(i) $2\vec{F}$<br>(ii) $-\vec{F}$<br>(iii) $0.5\vec{F}$<br>(iv) $-1.5\vec{F}$<br>(v) $-0.5\vec{F}$.
✓ Correct Answer: (i) 8 cm at 45°, (ii) 4 cm at 225°, (iii) 2 cm at 45°, (iv) 6 cm at 225°, (v) 2 cm at 225°
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Geometrical & Scalar Properties:</strong><br>Given: $|\vec{F}| = 4\text{ cm}$ and direction $\theta = 45^\circ$.<br>• If scalar $k > 0$, the vector maintains direction $\theta = 45^\circ$ and length becomes $k|\vec{F}|$.<br>• If scalar $k < 0$, the direction reverses by $180^\circ$ (new direction $\theta = 45^\circ + 180^\circ = 225^\circ$) and length is $|k||\vec{F}|$.<br><br><strong>(i) $2\vec{F}$:</strong><br>• Length $= 2 \times 4\text{ cm} = 8\text{ cm}$.<br>• Direction $= 45^\circ$ (Same direction as $\vec{F}$).<br><br><strong>(ii) $-\vec{F}$:</strong><br>• Length $= |-1| \times 4\text{ cm} = 4\text{ cm}$.<br>• Direction $= 45^\circ + 180^\circ = 225^\circ$ (Directly opposite to $\vec{F}$).<br><br><strong>(iii) $0.5\vec{F}$:</strong><br>• Length $= 0.5 \times 4\text{ cm} = 2\text{ cm}$.<br>• Direction $= 45^\circ$ (Same direction as $\vec{F}$).<br><br><strong>(iv) $-1.5\vec{F}$:</strong><br>• Length $= |-1.5| \times 4\text{ cm} = 6\text{ cm}$.<br>• Direction $= 45^\circ + 180^\circ = 225^\circ$ (Opposite direction).<br><br><strong>(v) $-0.5\vec{F}$:</strong><br>• Length $= |-0.5| \times 4\text{ cm} = 2\text{ cm}$.<br>• Direction $= 45^\circ + 180^\circ = 225^\circ$ (Opposite direction).
Sample Question 3
Exercise 7.1 - Vector Arithmetic on Compass Bearings
MEDIUM • Long Question
Given vectors $\vec{a} = 3\text{ units West}$ ($[-3, 0]$) and $\vec{b} = 3\text{ units North}$ ($[0, 3]$). Compute the component form and magnitude of the following combinations:<br>(i) $2\vec{a} + \vec{b}$<br>(ii) $\vec{a} - 2\vec{b}$<br>(iii) $3\vec{a} + 1.5\vec{b}$<br>(iv) $(2\vec{a} + \vec{b}) + (\vec{a} - 2\vec{b})$<br>(v) $0.5(\vec{a} + \vec{b})$<br>(vi) $3\vec{a} - 2\vec{b}$<br>(vii) $2\vec{a} - 2.5\vec{b}$<br>(viii) $-(\vec{a} - 2\vec{b})$.
✓ Correct Answer: (i) [-6, 3], (ii) [-3, -6], (iii) [-9, 4.5], (iv) [-9, -3], (v) [-1.5, 1.5], (vi) [-9, -6], (vii) [-6, -7.5], (viii) [3, 6]
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Algebraic Evaluation:</strong><br>Given: $\vec{a} = [-3, 0] = -3\hat{i}$ and $\vec{b} = [0, 3] = 3\hat{j}$.<br><br><strong>(i) $2\vec{a} + \vec{b}$:</strong><br>• $2[-3, 0] + [0, 3] = [-6, 0] + [0, 3] = [-6, 3] = -6\hat{i} + 3\hat{j}$.<br>• Magnitude $= \sqrt{(-6)^2 + 3^2} = \sqrt{36 + 9} = \sqrt{45} = 3\sqrt{5}\text{ units} \approx 6.71$.<br><br><strong>(ii) $\vec{a} - 2\vec{b}$:</strong><br>• $[-3, 0] - 2[0, 3] = [-3, 0] - [0, 6] = [-3, -6] = -3\hat{i} - 6\hat{j}$.<br>• Magnitude $= \sqrt{(-3)^2 + (-6)^2} = \sqrt{9 + 36} = \sqrt{45} = 3\sqrt{5}\text{ units} \approx 6.71$.<br><br><strong>(iii) $3\vec{a} + 1.5\vec{b}$:</strong><br>• $3[-3, 0] + 1.5[0, 3] = [-9, 0] + [0, 4.5] = [-9, 4.5] = -9\hat{i} + 4.5\hat{j}$.<br>• Magnitude $= \sqrt{(-9)^2 + (4.5)^2} = \sqrt{81 + 20.25} = \sqrt{101.25} = 4.5\sqrt{5}\text{ units} \approx 10.06$.<br><br><strong>(iv) $(2\vec{a} + \vec{b}) + (\vec{a} - 2\vec{b})$:</strong><br>• Combining like terms $= 3\vec{a} - \vec{b} = 3[-3, 0] - [0, 3] = [-9, -3] = -9\hat{i} - 3\hat{j}$.<br>• Magnitude $= \sqrt{(-9)^2 + (-3)^2} = \sqrt{81 + 9} = \sqrt{90} = 3\sqrt{10}\text{ units} \approx 9.49$.<br><br><strong>(v) $0.5(\vec{a} + \vec{b})$:</strong><br>• $0.5([-3, 0] + [0, 3]) = 0.5[-3, 3] = [-1.5, 1.5] = -1.5\hat{i} + 1.5\hat{j}$.<br>• Magnitude $= \sqrt{(-1.5)^2 + (1.5)^2} = \sqrt{2.25 + 2.25} = \sqrt{4.5} = 1.5\sqrt{2}\text{ units} \approx 2.12$.<br><br><strong>(vi) $3\vec{a} - 2\vec{b}$:</strong><br>• $3[-3, 0] - 2[0, 3] = [-9, 0] - [0, 6] = [-9, -6] = -9\hat{i} - 6\hat{j}$.<br>• Magnitude $= \sqrt{(-9)^2 + (-6)^2} = \sqrt{81 + 36} = \sqrt{117} = 3\sqrt{13}\text{ units} \approx 10.82$.<br><br><strong>(vii) $2\vec{a} - 2.5\vec{b}$:</strong><br>• $2[-3, 0] - 2.5[0, 3] = [-6, 0] - [0, 7.5] = [-6, -7.5] = -6\hat{i} - 7.5\hat{j}$.<br>• Magnitude $= \sqrt{(-6)^2 + (-7.5)^2} = \sqrt{36 + 56.25} = \sqrt{92.25} \approx 9.60\text{ units}$.<br><br><strong>(viii) $-(\vec{a} - 2\vec{b})$:</strong><br>• $-[-3, -6] = [3, 6] = 3\hat{i} + 6\hat{j}$.<br>• Magnitude $= \sqrt{3^2 + 6^2} = \sqrt{9 + 36} = 3\sqrt{5}\text{ units} \approx 6.71$.
Sample Question 4
Exercise 7.1 - Vector Scalar Proportions
MEDIUM • Short Question
In the coordinate grid, the direction and displacement of vector $\vec{a}$ is $4$ square units to the right and $3$ square units up (i.e., $\vec{a} = [4, 3]$). Determine the scalar relationship of the following vectors with $\vec{a}$:<br>(i) Vector $\vec{p} = [8, 6]$<br>(ii) Vector $\vec{q} = [-4, -3]$<br>(iii) Vector $\vec{r} = [-8, -6]$<br>(iv) Vector $\vec{s} = [2, 1.5]$<br>(v) Vector $\vec{t} = [-2, -1.5]$.
✓ Correct Answer: (i) p = 2a, (ii) q = -a, (iii) r = -2a, (iv) s = 0.5a, (v) t = -0.5a
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Scalar Relationship Analysis:</strong><br>Given reference vector: $\vec{a} = [4, 3] = 4\hat{i} + 3\hat{j}$.<br>We test for scalar multiple $k$ such that $\vec{v} = k\vec{a} = [4k, 3k]$:<br><br><strong>(i) Vector $\vec{p} = [8, 6]$:</strong><br>• $[8, 6] = 2[4, 3] = 2\vec{a}$.<br>• $\vec{p}$ is parallel and has twice the magnitude in the same direction.<br><br><strong>(ii) Vector $\vec{q} = [-4, -3]$:</strong><br>• $[-4, -3] = -1[4, 3] = -\vec{a}$.<br>• $\vec{q}$ is the negative vector of $\vec{a}$ (equal magnitude, opposite direction).<br><br><strong>(iii) Vector $\vec{r} = [-8, -6]$:</strong><br>• $[-8, -6] = -2[4, 3] = -2\vec{a}$.<br>• $\vec{r}$ is anti-parallel with twice the magnitude.<br><br><strong>(iv) Vector $\vec{s} = [2, 1.5]$:</strong><br>• $[2, 1.5] = 0.5[4, 3] = 0.5\vec{a} = \frac{1}{2}\vec{a}$.<br>• $\vec{s}$ is half the magnitude in the same direction.<br><br><strong>(v) Vector $\vec{t} = [-2, -1.5]$:</strong><br>• $[-2, -1.5] = -0.5[4, 3] = -0.5\vec{a} = -\frac{1}{2}\vec{a}$.<br>• $\vec{t}$ is half the magnitude in the opposite direction.
Sample Question 5
Exercise 7.1 - Point Translation by Vector
MEDIUM • Short Question
A point with coordinates $P(5, -7)$ is translated by the vector $\vec{v} = [0, 4]$. Find the new position $P'$ of the point.
✓ Correct Answer: P'(5, -3)
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Translation Formula:</strong><br>• <strong>Step 1:</strong> State the translation transformation rule.<br>If a point $P(x, y)$ is translated by vector $\vec{v} = [a, b]$, the translated coordinates $P'(x', y')$ are given by:<br>$$P'(x', y') = (x + a, y + b)$$<br>• <strong>Step 2:</strong> Substitute given values $x = 5, y = -7, a = 0, b = 4$:<br>$$x' = 5 + 0 = 5$$<br>$$y' = -7 + 4 = -3$$<br>• <strong>Step 3:</strong> Conclude the final coordinates.<br>$$P' = (5, -3)$$
Sample Question 6
Exercise 7.1 - Vector Translation
MEDIUM • Short Question
A vector $\vec{u} = [-5, 4]$ is translated by another vector $\vec{v} = [4, -3]$. Find the resultant location and combined translation of the vector.
✓ Correct Answer: [-1, 1] or -i + j
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Vector Addition:</strong><br>• <strong>Step 1:</strong> Apply the algebraic law for successive vector translation:<br>$$\vec{w} = \vec{u} + \vec{v} = [x_1 + x_2, y_1 + y_2]$$<br>• <strong>Step 2:</strong> Add corresponding components:<br>$$\vec{w} = [-5 + 4, 4 + (-3)] = [-1, 1]$$<br>• <strong>Step 3:</strong> In standard unit basis form:<br>$$\vec{w} = -\hat{i} + \hat{j}$$
Sample Question 7
Exercise 7.1 - Polygon Geometric Translation
MEDIUM • Short Question
Triangle $ABC$ has vertices $A(-4, 6)$, $B(-1, 4)$, and $C(-6, 1)$. Find the coordinates of the translated image vertices if:<br>(i) The triangle is translated by vector $\vec{v}_1 = [5, 0]$<br>(ii) The triangle is translated by vector $\vec{v}_2 = [-2, -4]$.
✓ Correct Answer: (i) A'(1, 6), B'(4, 4), C'(-1, 1); (ii) A''(-6, 2), B''(-3, 0), C''(-8, -3)
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Transformation:</strong><br><strong>(i) Translation by $\vec{v}_1 = [5, 0]$:</strong><br>Add $+5$ to $x$-coordinates and $+0$ to $y$-coordinates:<br>• $A' = (-4 + 5, 6 + 0) = (1, 6)$<br>• $B' = (-1 + 5, 4 + 0) = (4, 4)$<br>• $C' = (-6 + 5, 1 + 0) = (-1, 1)$<br><br><strong>(ii) Translation by $\vec{v}_2 = [-2, -4]$:</strong><br>Add $-2$ to $x$-coordinates and $-4$ to $y$-coordinates:<br>• $A'' = (-4 - 2, 6 - 4) = (-6, 2)$<br>• $B'' = (-1 - 2, 4 - 4) = (-3, 0)$<br>• $C'' = (-6 - 2, 1 - 4) = (-8, -3)$
Sample Question 8
Exercise 7.1 - Inverse Translation Vector
MEDIUM • Short Question
What translation vector $\vec{T}$ is required to map the point $E(-6, 5)$ directly onto the origin $O(0, 0)$?
✓ Correct Answer: [6, -5] or 6i - 5j
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Solution:</strong><br>• <strong>Step 1:</strong> Let the translation vector be $\vec{T} = [a, b]$.<br>• <strong>Step 2:</strong> Set up the translation equation for mapping $E$ to $O$:<br>$$E(x, y) + \vec{T} = O(0, 0) \implies (-6 + a, 5 + b) = (0, 0)$$<br>• <strong>Step 3:</strong> Equate individual components:<br>$$-6 + a = 0 \implies a = 6$$<br>$$5 + b = 0 \implies b = -5$$<br>• <strong>Step 4:</strong> Write the translation vector:<br>$$\vec{T} = [6, -5] = 6\hat{i} - 5\hat{j}$$
Sample Question 9
Exercise 7.1 - Vector Representation in Rectangle
MEDIUM • Long Question
$ABCD$ is a rectangle where $\vec{AB} = \vec{a}$, $\vec{BC} = \vec{b}$, and $O$ is the intersection of its diagonals. Express each of the following vectors in terms of $\vec{a}$ and $\vec{b}$:<br>(i) $\vec{CD}$<br>(ii) $\vec{DA}$<br>(iii) $\vec{AC}$<br>(iv) $\vec{BD}$<br>(v) $\vec{AO}$<br>(vi) $\vec{BO}$<br>(vii) $\vec{AB}$.
✓ Correct Answer: (i) -a, (ii) -b, (iii) a + b, (iv) b - a, (v) 0.5(a + b), (vi) 0.5(b - a), (vii) a
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Geometrical Derivations:</strong><br>In rectangle $ABCD$, opposite sides are equal in length and parallel: $\vec{AB} = \vec{DC} = \vec{a}$ and $\vec{BC} = \vec{AD} = \vec{b}$.<br><br><strong>(i) $\vec{CD}$:</strong><br>• $\vec{CD} = -\vec{DC} = -\vec{AB} = -\vec{a}$.<br><br><strong>(ii) $\vec{DA}$:</strong><br>• $\vec{DA} = -\vec{AD} = -\vec{BC} = -\vec{b}$.<br><br><strong>(iii) $\vec{AC}$:</strong><br>• By triangle law in $\triangle ABC$: $\vec{AC} = \vec{AB} + \vec{BC} = \vec{a} + \vec{b}$.<br><br><strong>(iv) $\vec{BD}$:</strong><br>• In $\triangle BCD$: $\vec{BD} = \vec{BC} + \vec{CD} = \vec{b} + (-\vec{a}) = \vec{b} - \vec{a} = -\vec{a} + \vec{b}$.<br><br><strong>(v) $\vec{AO}$:</strong><br>• In a rectangle, diagonals bisect each other, so $O$ is the midpoint of $AC$:<br>$$\vec{AO} = \frac{1}{2}\vec{AC} = \frac{1}{2}(\vec{a} + \vec{b})$$<br><br><strong>(vi) $\vec{BO}$:</strong><br>• $O$ is the midpoint of diagonal $BD$, so $\vec{BO} = \frac{1}{2}\vec{BD} = \frac{1}{2}(\vec{b} - \vec{a}) = \frac{1}{2}\vec{b} - \frac{1}{2}\vec{a}$.<br><br><strong>(vii) $\vec{AB}$:</strong><br>• Directly given: $\vec{AB} = \vec{a}$.
Sample Question 10
Exercise 7.1 - Position Vectors and Midpoint
MEDIUM • Short Question
Given that $\vec{OP} = \vec{p}$, $\vec{OQ} = \vec{q}$, and $M$ is the midpoint of the line segment $PQ$. Find the following vectors in terms of $\vec{p}$ and $\vec{q}$:<br>(i) $\vec{PQ}$<br>(ii) $\vec{PM}$<br>(iii) $\vec{QM}$<br>(iv) $\vec{OM}$.
✓ Correct Answer: (i) q - p, (ii) 0.5(q - p), (iii) 0.5(p - q), (iv) 0.5(p + q)
📖 Step-by-Step Solution & Conceptual Rationale:
<strong>Step-by-Step Derivation:</strong><br><strong>(i) $\vec{PQ}$:</strong><br>• By position vector formula: $\vec{PQ} = \vec{OQ} - \vec{OP} = \vec{q} - \vec{p}$.<br><br><strong>(ii) $\vec{PM}$:</strong><br>• Since $M$ is the midpoint of $PQ$: $\vec{PM} = \frac{1}{2}\vec{PQ} = \frac{1}{2}(\vec{q} - \vec{p}) = \frac{1}{2}\vec{q} - \frac{1}{2}\vec{p}$.<br><br><strong>(iii) $\vec{QM}$:</strong><br>• $\vec{QM} = -\vec{MQ} = -\vec{PM} = -\frac{1}{2}(\vec{q} - \vec{p}) = \frac{1}{2}(\vec{p} - \vec{q}) = \frac{1}{2}\vec{p} - \frac{1}{2}\vec{q}$.<br><br><strong>(iv) $\vec{OM}$:</strong><br>• By midpoint position vector formula: $\vec{OM} = \frac{\vec{OP} + \vec{OQ}}{2} = \frac{\vec{p} + \vec{q}}{2} = \frac{1}{2}\vec{p} + \frac{1}{2}\vec{q}$.