Question

A solid sphere mass $1kg$, radius $10cm$ rolls down an inclined plane of height $7m$ . The velocity of its centre as it reaches the ground level is.

• A. $7.7m{s}^{-1}$
• B. $11.7m{s}^{-1}$
• C. $15.7m{s}^{-1}$
• D. $20m{s}^{-1}$

Answer 1

The correct option is B $11.7m{s}^{-1}$

Here the velocity of center of mass has been asked so we need to consider $only$ the $translational$ motion so

$v=\sqrt{2gh}=\sqrt{2\times 9.8\times 7}=11.71m/s$