If a solid sphere of mass 1 kg rolls with linear speed of 1m/s, then the rolling kinetic energy will be

Options

A. 0.7 J
B. 1.4 J
C. 2.1 J
D. 2.8 J

Answer

A

Explanation

`KE_("roll")=(1)/(2)mv^(2)[1+(K^(2))/(R^(2))]`
`=(1)/(2)xx1xx1xx[1+(2)/(5)]=(1)/(2)xx(7)/(5)`
= 0.7 J