Question

A solid sphere of mass 1 kg rolls on a rough table with linear speed 1 m/s. Its total kinetic energy is:

• A. 1 J
• B. 0.5 J
• C. 0.7 J
• D. 1.4 J.

Answer 1

Answer: (C)

0.7 J

Answer 2

$\mathrm { K } _ { \mathrm { N } } = \frac { 1 } { 2 } \mathrm { mv } ^ { 2 } \left( 1 + \frac { \mathrm { K } ^ { 2 } } { \mathrm { R } ^ { 2 } } \right) = \frac { 1 } { 2 } \times 1 \times ( 1 ) ^ { 2 } \times \left( 1 + \frac { 2 } { 5 } \right) = 0.7 \mathrm {~J}$