Rotation 3 Question 15
21. A solid sphere is in pure rolling motion on an inclined surface having inclination $\theta$
$(2006,5$ M)
(a) frictional force acting on sphere is $f=\mu m g \cos \theta$
(b) $f$ is dissipative force
(c) friction will increase its angular velocity and decrease its linear velocity
(d) If $\theta$ decreases, friction will decrease
Numerical Value Based Question
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Answer:
Correct Answer: 21. (c, d)
Solution:
- In case of pure rolling,
$$ \begin{aligned} & f=\frac{m g \sin \theta}{1+\frac{m R^{2}}{I}} \\ \therefore \quad & f \propto \sin \theta \end{aligned} $$
Therefore, as $\theta$ decreases force of friction will also decrease.
