Question

A body is rolling without slipping on a horizontal surface and its rotational kinetic energy is equal to the translational kinetic energy. The body is:

• A. Disc
• B. Sphere
• C. Cylinder
• D. Ring

Answer 1

Answer: (D)

Ring

Answer 2

⇒ $\frac { 1 } { 2 } m v ^ { 2 } \left( \frac { K ^ { 2 } } { R ^ { 2 } } \right) = \frac { 1 } { 2 } m v ^ { 2 }$ ⇒ $\frac { K ^ { 2 } } { R ^ { 2 } } = 1$

i.e. the body is ring