What Is the Turning Point Concept in Physics?

[Soaring Crane]

We did a lab to illustrate this concept in class. The problem is I have no idea what this concept is trying to show. Basically the length of a string was altered from 30 cm to 80 cm. Then, at a 90 degree angle from the vertical of the pole housing the meter stick and the attached string, it was released with a metal circular object. D, the distance to the point where it wraps around a horizontal rod, was measured.

The relationship that came about was D = (3/5)L.

The issue that I don't understand is the use of Ma = T + Mg and a = (v^2)/r to derive D = (3/5)L.

If anyone has an inkling of where I can get any physics info on this "concept" or if you can help, please respond. Thanks.

 

[Nate810]

The concept being illustrated is the relationship between angular momentum and linear momentum. Angular momentum is a measure of how much an object's momentum is rotating around an axis, whereas linear momentum is a measure of the speed and direction in which an object is moving. In order for an object to move in a circular motion, it must have both a tangential (linear) and radial (angular) component of its momentum. In the lab you described, the string was attached to the meter stick at an angle of 90 degrees, meaning that its linear momentum was perpendicular to the direction of rotation. As the string was released, the metal circular object would rotate around the horizontal rod, with the distance D (from the point of release to the point where it wrapped around the rod) being equal to the ratio between the linear momentum and the angular momentum. This ratio is represented by the equation D = (3/5)L, where L is the length of the string. The equations Ma = T + Mg and a = (v^2)/r were used to calculate the angular and linear momentum, respectively. Ma is the angular momentum of the object, T is the torque (the force causing the rotation), Mg is the gravitational force acting on the object, a is the acceleration of the object, v is the tangential velocity (the speed of the object in the direction of rotation), and r is the radius of the circle the object is rotating around.

 

[wais]

The Turning Point Concept is a physics concept that refers to the point at which an object changes direction due to the forces acting upon it. In your lab, the concept was demonstrated by altering the length of a string and releasing a metal circular object at a 90 degree angle from a vertical pole. The distance, D, at which the object wraps around a horizontal rod was then measured.

The relationship between the length of the string (L) and the distance (D) was found to be D = (3/5)L. This relationship can be derived using the equations Ma = T + Mg and a = (v^2)/r, where Ma represents the net force acting on the object, T represents the tension in the string, Mg represents the force of gravity, a represents the acceleration of the object, v represents its velocity, and r represents the radius of the circular motion.

By manipulating these equations, it can be shown that the distance D is equal to 3/5 of the length of the string L. This relationship demonstrates the concept of the turning point, as the change in direction of the object is directly related to the length of the string.

If you are looking for more information on this concept, you can consult your physics textbook or do some online research. You can also ask your instructor for further clarification or explanation. Understanding the underlying principles and equations involved in this concept will help you better understand the results of your lab and the concept itself.