Question

A sphere of mass 0.5 kg and diameter 1m rools without sliding with a constant velocity of 5 m/s,calculate what is the ratio of the rotational K.E. to the total kinetic energy of th sphere:

• A. 7/10
• B. 5/7
• C. 2/7
• D. 1/2.

Answer 1

Answer: (C)

2/7

Answer 2

$\frac { \mathrm { K } _ { \mathrm { R } } } { \mathrm { K } _ { \mathrm { N } } } = \frac { \mathrm { K } ^ { 2 } / \mathrm { R } ^ { 2 } } { 1 + \mathrm { K } ^ { 2 } / \mathrm { R } ^ { 2 } } = \frac { 2 / 5 } { 1 + 2 / 5 } = 2 / 7$