This grindstone has a mass of 60 kg, a diameter of 0.600 m and has a moment of Inertia (I) of 4.50 kg.m2. There is a constant friction torque of 5 N.m. at the bearings. (a) You press a knife down on the rim of the grindstone with a normal force of 50N. The coefficient of friction between the knife and the stone is 0.60. How much force must be applied to the outer edge of the grindstone to maintain a constant angular velocity of 120 revolutions per minutes b) How much time does it take for the grindstone to go from 120 revolutions per minute to rest if it is acted up by the bearings friction alone?
Angular speed, acceleration and displacement
Angular acceleration is defined as the rate of change in angular velocity with respect to time. It has both magnitude and direction. So, it is a vector quantity.
Angular Position
Before diving into angular position, one should understand the basics of position and its importance along with usage in day-to-day life. When one talks of position, it’s always relative with respect to some other object. For example, position of earth with respect to sun, position of school with respect to house, etc. Angular position is the rotational analogue of linear position.
This grindstone has a mass of 60 kg, a diameter of 0.600 m and has a moment of Inertia (I) of 4.50 kg.m2. There is a constant friction torque of 5 N.m. at the bearings.
(a) You press a knife down on the rim of the grindstone with a normal force of 50N. The coefficient of friction between the knife and the stone is 0.60. How much force must be applied to the outer edge of the grindstone to maintain a constant
b) How much time does it take for the grindstone to go from 120 revolutions per minute to rest if it is acted up by the bearings friction alone?
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