Normal Forces

Problem:

Do inanimate objects object forces?

What is the nature of the "normal" force?

Materials:

An embroidery hoop with 1 piece of cloth, an embroidery hoop with 2 pieces of cloth, a table top, a wall, a 50 g and 100 g mass.

Procedure:

1. Hold the one-cloth embroidery hoop upright and with your fingers press the center of the cloth perpendicular to the cloth surface. What does your finger feel? What happens to the cloth surface?

1. Press harder in the center of the cloth surface. Now what does your finger feel? What happens to the cloth surface?

2. Repeat parts (1) and (2) using the two-cloth hoop. Does the surface bend more or less than it did when one cloth was used?

3. Do a similar set of investigations using the same hoops held horizontally with 50g, then 100g, and finally 150g masses placed in the center of each.