question_answer

    A particle is kept at rest at the top of a sphere of diameter 42 m. When disturbed slightly, it slides down. At what height h from the bottom, the particle will leave the sphere

A)  14m                     

B)  28m

C)  35m                     

D)  7m

Correct Answer: C

Solution :

                The condition of slipping by particle from top is given by                 \[\cos \theta =\frac{2}{3}\] From the figure,                 \[h=r\cos \theta =21\times \frac{2}{3}=14\,m\] Therefore, .the required height at which the particle will leave the the sphere is \[=21+h=21+14=35m\]