1.) A clock has a second hand which rubs against the inside of the glass cover. If the frictional force between the glass cover and the tip of the hand is 0.0020 N and the length of the hand is 8 cm, what minimum torque must be supplied to the hand by the clock mechanism if the hand is not to stop?
2.) The figure shows four masses held at the corners of a rectangle by light rods. Find the moment of rotational inertia a) about the x-axis. b) about the y-axis. c) about the z-axis (perpendicular to the page, passing through the origin).
What magnitude torque is necessary to give the object an angular acceleration of 1.5 rad/s2 a) along the x-axis? b) along the y-axis? c) along the z-axis (perpendicular to the page, passing through the origin)?