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प्रश्न
A solid sphere of mass 0⋅50 kg is kept on a horizontal surface. The coefficient of static friction between the surfaces in contact is 2/7. What maximum force can be applied at the highest point in the horizontal direction so that the sphere does not slip on the surface?
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उत्तर
Let α be the angular acceleration produced in the sphere.

Rotational equation of motion,
\[F \times R - f_r \times R = I\alpha\]
\[\Rightarrow F = \frac{2}{5}mR\alpha + \mu mg........(1)\]
Translational equation of motion,
\[F = ma - \mu mg\]
\[ \Rightarrow a = \frac{\left( F + \mu mg \right)}{m}\]
For pure rolling, we have
\[\alpha = \frac{a}{R}\]
\[\Rightarrow \alpha = \frac{\left( F + \mu mg \right)}{mR}\]
Putting the value of \[\alpha\] in equation (1), we get
\[F = \frac{2}{5}\frac{mR\left( F + \mu mg \right)}{mR} + \mu mg\]
\[ \Rightarrow F = \frac{2}{5}\left( F + \mu mg \right) \mu mg\]
\[ \Rightarrow F = \frac{2}{5}F + \left( \frac{2}{5} \times \frac{2}{7} \times 0 . 5 \times 10 \right) + \left( \frac{2}{7} \times 0 . 5 \times 10 \right)\]
\[ \Rightarrow \frac{3F}{5} = \frac{4}{7} + \frac{10}{7} = 2\]
\[ \Rightarrow F = \frac{5 \times 2}{3} = \frac{10}{3} = 3 . 3 N\]
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संबंधित प्रश्न
A solid sphere rolls down two different inclined planes of the same heights but different angles of inclination. (a) Will it reach the bottom with the same speed in each case? (b) Will it take longer to roll down one plane than the other? (c) If so, which one and why?
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