A disc with a radius of 0.62 m and mass 4 kg is fixed to rotate about its center. Three forces act on the object as noted below. At what time will the rotational kinetic energy of the disc be 672 if it started from rest? The moment of inertia for a solid disc is 0.5MR2 F1 = 10.9 N tangentially applied to the outer edge. F2 = 11.5 N tangentially applied to the outer edge. F3 = 10.3 N tangentially applied at a distance 0.38 m above the axis of rotation at an angle theta = 34 degrees with respect to the vertical.
Angular Momentum
The momentum of an object is given by multiplying its mass and velocity. Momentum is a property of any object that moves with mass. The only difference between angular momentum and linear momentum is that angular momentum deals with moving or spinning objects. A moving particle's linear momentum can be thought of as a measure of its linear motion. The force is proportional to the rate of change of linear momentum. Angular momentum is always directly proportional to mass. In rotational motion, the concept of angular momentum is often used. Since it is a conserved quantity—the total angular momentum of a closed system remains constant—it is a significant quantity in physics. To understand the concept of angular momentum first we need to understand a rigid body and its movement, a position vector that is used to specify the position of particles in space. A rigid body possesses motion it may be linear or rotational. Rotational motion plays important role in angular momentum.
Moment of a Force
The idea of moments is an important concept in physics. It arises from the fact that distance often plays an important part in the interaction of, or in determining the impact of forces on bodies. Moments are often described by their order [first, second, or higher order] based on the power to which the distance has to be raised to understand the phenomenon. Of particular note are the second-order moment of mass (Moment of Inertia) and moments of force.
A disc with a radius of 0.62 m and mass 4 kg is fixed to rotate about its center. Three forces act on the object as noted below. At what time will the rotational kinetic energy of the disc be 672 if it started from rest? The moment of inertia for a solid disc is 0.5MR2
F1 = 10.9 N tangentially applied to the outer edge.
F2 = 11.5 N tangentially applied to the outer edge.
F3 = 10.3 N tangentially applied at a distance 0.38 m above the axis of rotation at an angle theta = 34 degrees with respect to the vertical.
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