Questions where an object sits on a rotating disc or turntable and friction determines the condition for slipping, asking for maximum radius, angular velocity, or critical distance.
A coin placed on a rotating table just slips when it is placed at a distance of 1 cm from the centre. If the angular velocity of the table is halved, it will just slip when placed at a distance of $\_\_\_\_$ from the centre: (1) 8 cm (2) 4 cm (3) 1 cm (4) 2 cm