Question

When a solid sphere rolls without slipping on a surface, its rotational kinetic energy is 40 J. Then its total kinetic energy is
A. 100 J
B. 70 J
C. 140 J
D. 280 J

Answer 1

Correct Answer - C
`T E_(2)=(1)/(2)I omega 2+(1)/(2)mv^(2)=40 +(1)/(2)m R^(2)omega^(2)`
`= 40+(1)/(2)((2)/(5)mR^(2)omega^(2))xx(5)/(2)=40+40xx(5)/(2)`
= 140 J