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A particle is projected from the surface...

A particle is projected from the surface of earth of mass M and radius R with speed `v`. Suppose it travels a distance `x(lt lt R)` when its speed becomes `v` to `v//2` and `y(lt lt R)` when speed changes from `v//2` to 0. Similarly, the corresponding times are suppose `t_(1) and t_(2)`. Then
`{:(,"Column-I",,"Column-II"),("(A)",x//y,"(p)",=1),("(B)",t_(1)//t_(2),"(r)",gt 1),(,,"(r)",lt 1):}`

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To solve the problem, we need to analyze the motion of a particle projected from the surface of the Earth. We will use the equations of motion under uniform acceleration due to gravity. ### Step 1: Analyze the first segment of motion (from speed `v` to `v/2`) 1. **Initial conditions**: - Initial speed, \( u = v \) - Final speed, \( v' = \frac{v}{2} \) - Acceleration, \( a = -g \) (negative because gravity acts downwards) 2. **Using the equation of motion**: \[ v' = u - g t_1 \] Substituting the values: \[ \frac{v}{2} = v - g t_1 \] Rearranging gives: \[ g t_1 = v - \frac{v}{2} = \frac{v}{2} \] Thus, \[ t_1 = \frac{v}{2g} \] 3. **Finding distance \( x \)**: Using the second equation of motion: \[ v'^2 = u^2 - 2g x \] Substituting the values: \[ \left(\frac{v}{2}\right)^2 = v^2 - 2g x \] This simplifies to: \[ \frac{v^2}{4} = v^2 - 2g x \] Rearranging gives: \[ 2g x = v^2 - \frac{v^2}{4} = \frac{3v^2}{4} \] Therefore, \[ x = \frac{3v^2}{8g} \] ### Step 2: Analyze the second segment of motion (from speed `v/2` to `0`) 1. **Initial conditions**: - Initial speed, \( u = \frac{v}{2} \) - Final speed, \( v' = 0 \) 2. **Using the equation of motion**: \[ 0 = \frac{v}{2} - g t_2 \] Rearranging gives: \[ g t_2 = \frac{v}{2} \] Thus, \[ t_2 = \frac{v}{2g} \] 3. **Finding distance \( y \)**: Using the second equation of motion: \[ 0 = \left(\frac{v}{2}\right)^2 - 2g y \] This simplifies to: \[ 0 = \frac{v^2}{4} - 2g y \] Rearranging gives: \[ 2g y = \frac{v^2}{4} \] Therefore, \[ y = \frac{v^2}{8g} \] ### Step 3: Compare \( \frac{x}{y} \) and \( \frac{t_1}{t_2} \) 1. **Calculating \( \frac{x}{y} \)**: \[ \frac{x}{y} = \frac{\frac{3v^2}{8g}}{\frac{v^2}{8g}} = 3 \] Thus, \( \frac{x}{y} = 3 > 1 \). 2. **Calculating \( \frac{t_1}{t_2} \)**: \[ \frac{t_1}{t_2} = \frac{\frac{v}{2g}}{\frac{v}{2g}} = 1 \] Thus, \( \frac{t_1}{t_2} = 1 \). ### Conclusion - From the calculations: - \( \frac{x}{y} = 3 \) (greater than 1) - \( \frac{t_1}{t_2} = 1 \) ### Final Matching - (A) \( \frac{x}{y} \) matches with (r) \( > 1 \) - (B) \( \frac{t_1}{t_2} \) matches with (p) \( = 1 \)
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