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NEET
Exam
NEET
Subject
Physics
Chapter
Motion in Two Dimensions

NEET · Physics · Motion in Two Dimensions

The equation of motion of a projectile is y=a x-b x^2 , where a, b...

The equation of motion of a projectile is y=ax−bx2y=a x-b x^2, where a,ba, b are constants. Match the column - I with column - II Column - IColumn - IIi) The initial velocity of projectiona)abii) The horizontal range of projectileb)a2bgiii) The maximum height attained by projectilec)a24biv) The time of flight of projectiled)g(1+a2)2b\begin{array}{ll} \text{Column - I} & \text{Column - II} \\ \text{i) The initial velocity of projection} & \text{a)} \frac{a}{b} \\ \text{ii) The horizontal range of projectile} & \text{b)} a \sqrt{\frac{2}{\mathrm{bg}}} \\ \text{iii) The maximum height attained by projectile} & \text{c)} \frac{\mathrm{a}^2}{4 \mathrm{ b}} \\ \text{iv) The time of flight of projectile} & \text{d)} \sqrt{\frac{g\left(1+a^2\right)}{2 b}} \end{array}

Options

  1. A i  ii  iii  iv  a  b  c  d \begin{array}{cccc} \text{ i } & \text{ ii } & \text{ iii } & \text{ iv } \\ \text{ a } & \text{ b } & \text{ c } & \text{ d } \end{array}
  2. B i  ii  iii  iv  d  a  b  c \begin{array}{cccc} \text{ i } & \text{ ii } & \text{ iii } & \text{ iv } \\ \text{ d } & \text{ a } & \text{ b } & \text{ c } \end{array}
  3. C i  ii  iii  iv  d  a  c  b \begin{array}{cccc} \text{ i } & \text{ ii } & \text{ iii } & \text{ iv } \\ \text{ d } & \text{ a } & \text{ c } & \text{ b } \end{array}
  4. D i  ii  iii  iv  a  d  c  b \begin{array}{cccc}\text{ i } & \text{ ii } & \text{ iii } & \text{ iv } \\ \text{ a } & \text{ d } & \text{ c } & \text{ b }\end{array}

Correct answer

C.  i  ii  iii  iv  d  a  c  b \begin{array}{cccc} \text{ i } & \text{ ii } & \text{ iii } & \text{ iv } \\ \text{ d } & \text{ a } & \text{ c } & \text{ b } \end{array}

Step-by-step solution

Matching the Columns i) The initial velocity of projection From our derivation, (u=g(1+a2)2b\sqrt{\frac{g\left(1+a^2\right)}{2 b}}. This matches option d. ii) The horizontal range of a projectile The horizontal range, RR, is the value of xx when y=0y=0. y=ax−bx2=x(a−bx)=0y=a x-b x²=x(a-b x)=0 The solutions are x=0x=0 and (x=ab\frac{a}{b}. The range is the non-zero solution. (R=ab.\frac{a}{b} . This matches option a. iii) The maximum height attained by the projectile The maximum height, HH, occurs at the midpoint of the range, so at (x=R / 2=a2b\frac{a}{2 b}. Substitute this into the trajectory equation: (H=a(a2b)−\left(\frac{a}{2 b}\right)-b\left(\frac{a}{2 b}\right)^2=2=\frac{a^2}{2 b}-b(a24b2)=a22b−a24b=2a2−a24b=a24b.Thismatchesoptionc.iv)Theb\left(\frac{a^2}{4 b^2}\right)=\frac{a^2}{2 b}-\frac{a^2}{4 b}=\frac{2 a^2-a^2}{4 b}=\frac{a^2}{4 b} .This matches option c. iv) Thetime of flight of the projectile The time of flight, TT, is related to the range by the horizontal velocity: (R=u \cosθ⋅\theta \cdotT). (T=Rucos⁡θ=a/bu/1+tan⁡2θ=ab1+α2u.\frac{R}{u \cos \theta}=\frac{a / b}{u / \sqrt{1+\tan ^2 \theta}}=\frac{a}{b} \frac{\sqrt{1+\alpha^2}}{u} . Substitute our expression for uu : (T=ab1+a2(1+a2)2=ab(1+a2)2bg(1+a2)=ab2bg=a2bbg=ab2bg=a2bg=\frac{a}{b} \frac{\sqrt{1+a^2}}{\sqrt{\frac{\left(1+a^2\right)}{2}}}=\frac{a}{b} \sqrt{\frac{\left(1+a^2\right) 2 b}{g\left(1+a^2\right)}}=\frac{a}{b} \sqrt{\frac{2 b}{g}}=\frac{a \sqrt{2 b}}{b \sqrt{g}}=\frac{a}{b} \frac{\sqrt{2}}{\sqrt{b} \sqrt{g}}=\frac{a \sqrt{2}}{\sqrt{b} \sqrt{g}}=a 2bg.\sqrt{\frac{2}{b g}} . This matches option b. Final Matches - i →→ d - ii →→ a - iii →c→ c - iv →→ b This matches the configuration of option (3).
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