A solid, uniform cylinder (aka disk) of mass M = 3603 kg and radius R = 4.1 m can rotate about a FIXED axis at the center. The cylinder (disk) is subjected to a steady force applied at the right edge of the diameter shown. As you can see, the force is tangent to the cylinder rim. (a) Compute the moment of inertia I about the center. (b) What is the net torque τ about the center? (c) What is the cylinder's angular acceleration a? (d) Assume the cylinder (DISK) starts its rotation from rest when subjected to the force shown. What is the cylinder's angular velocity o after a time period of 30.0 seconds? What is the magnitude L of the angular momentum of the disk after a time period of 30.0 seconds? HINT: L=I*o. (f) Show that the time derivative of the GENERAL EXPRESSION of the angular momentum I*o equals the torque. 4.0 m ņ 25.0 N = F
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.
Step by step
Solved in 8 steps with 9 images
