Aclock has a second hand whose tip rubs against the inside of the glass cover. if the frictional force between the glass cover and the tip of the second hand is 0.0020 and the length of the hand is 8.0 cm, what is the minimum torque that must be applied to the second hand if the clock is not to be stopped? what is the direction of the torque from the friction?

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

Glass has a hardness that is in the middle of the hardness scale. what is the hardness of glass?