Question

A circular disc of mass 0.41 kg and radius 10 m rolls without slipping with a velocity of 2 m/s. The total kinetic energy of disc is:

• A. 0.41 J
• B. 1.23 J
• C. 0.82 J
• D. 2.4 J

Answer 1

Answer: (B)

1.23 J

Answer 2

$\mathrm { K } _ { \mathrm { N } } = \frac { 1 } { 2 } \mathrm { mv } ^ { 2 } \left( 1 + \frac { \mathrm { K } ^ { 2 } } { \mathrm { R } ^ { 2 } } \right) = \frac { 1 } { 2 } \times 0.41 \times ( 2 ) ^ { 2 } \times \left( \frac { 3 } { 2 } \right)$ $= 1.23 \mathrm {~J}$