Question

A gramophone record is revolving with an angular velocity w. A coin is placed at a distance R from the centre of the record. The static coefficient of friction is m. The coin will revolve with the record if –

• A. R > $\frac { \mu \mathrm { g } } { \omega ^ { 2 } }$
• B. R = $\frac { \mu \mathrm { g } } { \omega ^ { 2 } }$ only
• C. R < $\frac { \mu \mathrm { g } } { \omega ^ { 2 } }$
• D. R £ $\frac { \mu \mathrm { g } } { \omega ^ { 2 } }$

Answer 1

Answer: (D)

R £ $\frac { \mu \mathrm { g } } { \omega ^ { 2 } }$

Answer 2

mw²r £ mmg ̃ r £ mg/w²