The linear acceleration of a solid sphere is given by, a=‌
g‌sin‌θ
1+‌
I
MR2
=‌
g‌sin‌θ
1+‌
‌
2
5
MR2
MR2
=‌
5
7
g‌sin‌θ Apply Newton's second law of motion for linear motion of the centre of mass. mg‌sin‌θ−f‌‌=ma f‌‌=mg‌sin‌θ−ma ‌‌=mg‌sin‌θ−‌
5
7
mg‌sin‌θ ‌‌=‌
2
7
mg‌sin‌θ The coefficient of friction is calculated as, (µS)=‌