A coin is placed on a rotating turn table rotated with angular speed w. The coin just begins to slip if it is placed at 4 cm from the centre of the table. If the angular velocity is doubled, at what distance will the coin start to slip ?

A wheel starting from rest is rotating with constant angular acceleration of 2 rad/s^2 . A student notes that it traces an angle of 80 radians in 4 sec interval. What was the angular velocity of the wheel, when the student started his observation ?