A sphere is projected npon a rough inclined plane. The friction coefficient between the solid sphere and the incline is`mu`. The centre of the sphere is given an initial upward' velocity at `t=0` without imparting any initial angular velocity. Then, which of the following statement (s) is/are true?

Options

A. Pure rolling will defin!tely begin before the sphere reaches the highest point and the sphere will continue to roll purely after that, even while coming down.
B. Pure rolling will definitely begin before the sphere reaches the highest point but the sphere will continue to roll purely after that (even while coming down) only· if `mu` is greater- than a certain value.
C. The sphere will be rolling purely while coming down if `mu gt ((2tan alpha))/7`
D. The sphere cannot roll purely while moving up the incline

Answer

B, C