A disc of mass ' 1 Kg ' and radius ' 1 m ' is placed over the plank of mass '1 Kg '. A force of constant magnitude of ' 20 N ' is applied at the centre of the disc. If friction is sufficient enough to avoid slipping then the frictional force acting between the plank and the disc will be:
1 N
3 N
5 N
7 N
acceleration of the point of contact.
To avoid slipping, acceleration of the plank should be same