A star has the same size as the sun but with a mass five times as great. It rotates one revolution every five days about its axis. Suppose it collapsed into a neutron star, reducing its size to 75 percent of its original size and losing 10 percent of its mass in the process. What would be its angular speed? Assume the star to be a uniform sphere at all times. Neglect also the angular momentum accompanying the lost ma
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 star has the same size as the sun but with a mass five times as great. It rotates one revolution every five days about its axis. Suppose it collapsed into a neutron star, reducing its size to 75 percent of its original size and losing 10 percent of its mass in the process. What would be its angular speed? Assume the star to be a uniform sphere at all times. Neglect also the
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