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JEE Mains · Physics · STD 11 - 4.1 newtons laws of motion

A ball is thrown upward with an initial velocity \(V_0\) from the surface of the earth. The motion of the ball is affected by a drag force equal to \(m\gamma {v^2}\) (where \(m\) is mass of the ball, \(v\) is its Instantneous velocity and \(\gamma \) is a constant). Time taken by the ball to rise to its zenith is

  1. A \(\frac{1}{{\sqrt {\gamma g} }}\ln \left( {1 + \sqrt {\frac{\gamma }{g}} {V_0}} \right)\)
  2. B \(\frac{1}{{\sqrt {\gamma g} }}{\tan ^{ - 1}}\left( {\sqrt {\frac{\gamma }{g}} {V_0}} \right)\)
  3. C \(\frac{1}{{\sqrt {\gamma g} }}{\sin ^{ - 1}}\left( {\sqrt {\frac{\gamma }{g}} {V_0}} \right)\)
  4. D \(\frac{1}{{\sqrt {2\gamma g} }}{\tan ^{ - 1}}\left( {\sqrt {\frac{2\gamma }{g}} {V_0}} \right)\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\frac{1}{{\sqrt {\gamma g} }}{\tan ^{ - 1}}\left( {\sqrt {\frac{\gamma }{g}} {V_0}} \right)\)

Step-by-step Solution

Detailed explanation

\(\begin{array}{l} - \left( {g + \gamma {v^2}} \right) = \frac{{dv}}{{dt}}\\ - gdt = \frac{g}{\gamma }\left( {\frac{{dv}}{{\frac{g}{\gamma } + {v^2}}}} \right)\\ {\rm{integrating}}\,0\, \to \,t\,and\,{V_0} \to 0: \end{array}\)…
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