A thin light wire is wrapped around the edge of a wheel as shown in the figure. The wheel rotates frictionlesly around a fixed horizontal axis that passes through its center. The wheel is a smooth (uniform) disk of radius R = 0.28 m. A block with mass m = 4.20 kg is suspended from free end of the wire. The system is released and the suspended block lands with constant acceleration. If the suspended block travels 3 m down in 2 s, what is the mass of the wheel? (Take the moment of ineartia of the disk as I =1/2 MR2)
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 thin light wire is wrapped around the edge of a wheel as shown in the figure. The wheel rotates frictionlesly around a fixed horizontal axis that passes through its center. The wheel is a smooth (uniform) disk of radius R = 0.28 m. A block with mass m = 4.20 kg is suspended from free end of the wire. The system is released and the suspended block lands with constant acceleration. If the suspended block travels 3 m down in 2 s, what is the mass of the wheel? (Take the moment of ineartia of the disk as I =1/2 MR2)
Trending now
This is a popular solution!
Step by step
Solved in 5 steps with 5 images
