Pl ans q57 with reason.
Q.57. Ball bearings are used to
(A) Convert static to dynamic friction
(B) Convert limiting to dynamic friction
(C) Convert sliding to rolling friction
(D) Convert rolling friction to fluid friction

Dear student,
Answer : C 
Ball bearings are used to convert sliding friction to rolling friction. Rolling friction is much lesser than sliding friction. When we use ball bearings, it will further reduce the rotational friction by supporting radial and axial loads.
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