- #1
YeeHaa
- 28
- 4
Hi,
I'm doing some research on friction, and I did some tests with 4 different types of floor.
Now the first of these four floors is a sport surface (it has a polyurethane top coat), the second one is a floor-tile (with fabric on top), the third one a piece of foam and the fourth a piece of wood.
All of these materials were tested against metal.
Now I tested every floor with 3 different weights, and took some measurements (measured the normal force and friction force).
When I look at the Coefficient of Friction, it seems that for the first two floors (sport surface and floor tile), the Coefficient of Friction is LARGER when the weight is SMALLER. As soon as I increase the weight (2nd and 3rd weight), the Coefficient of Friction stays the same (it's the same for both weights).
Could this have to do with Amonton's Second Law? Maybe less weight means the surface deformes little.. (but in my eyes this would mean that friction should be lower), and with a lot of weight more of the surface at microscopic level touches the metal?
Some numbers:
Sport surface - metal:
Weight 1: (about 9 kg): CoF = 0.27
Weight 2: (about 15 kg): CoF = 0.19 (+/-)
Weight 3: (about 25 kg): CoF = 0.19 (+/-)
Floor tile - metal (same as sport surface, guess that's coincidence)
Weight 1: (about 9 kg): CoF = 0.27
Weight 2: (about 15 kg): CoF = 0.19 (+/-)
Weight 3: (about 25 kg): CoF = 0.19 (+/-)
Foam - metal:
Weight 1: (about 9 kg): CoF = 0.42
Weight 2: (about 15 kg): CoF = 0.43 (+/-)
Weight 3: (about 25 kg): CoF = 0.41 (+/-)
Wood - metal:
Weight 1: (about 9 kg): CoF = 0.11
Weight 2: (about 15 kg): CoF = 0.12(+/-)
Weight 3: (about 25 kg): CoF = 0.11(+/-)
I'm doing some research on friction, and I did some tests with 4 different types of floor.
Now the first of these four floors is a sport surface (it has a polyurethane top coat), the second one is a floor-tile (with fabric on top), the third one a piece of foam and the fourth a piece of wood.
All of these materials were tested against metal.
Now I tested every floor with 3 different weights, and took some measurements (measured the normal force and friction force).
When I look at the Coefficient of Friction, it seems that for the first two floors (sport surface and floor tile), the Coefficient of Friction is LARGER when the weight is SMALLER. As soon as I increase the weight (2nd and 3rd weight), the Coefficient of Friction stays the same (it's the same for both weights).
Could this have to do with Amonton's Second Law? Maybe less weight means the surface deformes little.. (but in my eyes this would mean that friction should be lower), and with a lot of weight more of the surface at microscopic level touches the metal?
Some numbers:
Sport surface - metal:
Weight 1: (about 9 kg): CoF = 0.27
Weight 2: (about 15 kg): CoF = 0.19 (+/-)
Weight 3: (about 25 kg): CoF = 0.19 (+/-)
Floor tile - metal (same as sport surface, guess that's coincidence)
Weight 1: (about 9 kg): CoF = 0.27
Weight 2: (about 15 kg): CoF = 0.19 (+/-)
Weight 3: (about 25 kg): CoF = 0.19 (+/-)
Foam - metal:
Weight 1: (about 9 kg): CoF = 0.42
Weight 2: (about 15 kg): CoF = 0.43 (+/-)
Weight 3: (about 25 kg): CoF = 0.41 (+/-)
Wood - metal:
Weight 1: (about 9 kg): CoF = 0.11
Weight 2: (about 15 kg): CoF = 0.12(+/-)
Weight 3: (about 25 kg): CoF = 0.11(+/-)