Chapter 8, Problem 1RQ

To determine

The place or point where a nail is to be kept, so that an oval framed painting is correctly oriented in both the vertical and horizontal directions.

Answer to Problem 1RQ

Solution:

The oval cardboard will have two centroids. The nail should be placed at the center of mass of the oval shaped painting, which is located at the midpoint of the line connecting the two centroids.

Explanation of Solution

Introduction:

Center of mass is a point where the complete mass of any object is said to be concentrated. Whenever a force is applied on the body leading to its motion, it can be simplified by taking that force over the center of mass.

Explanation:

In the oval cardboard, there will be two centroids, the Center of mass will be on the midpoint of the line connecting the two centroids. When a single nail is kept under the point, it will hold the complete oval painting without any disorientation. This happens because the force due to gravity is concentrated at the point and is balanced with the upward force given by the pin on the Centre of mass.

Conclusion:

Hence, the nail should be placed at the midpoint of the line connecting the two centroids in order to keep it oriented both horizontally a well as vertically.