- #1
terryds
- 392
- 13
In the tablecloth trick, if we pull the tablecloth with a great force, the objects on it will stay on the table. But, if we pull it gently, the objects on it will still get along with the cloth movement.
I know that if the force exceeds the maximum value of static friction, the objects will stay on the table.
But, I still don't understand two things.
1. What static friction should be exceeded to do the trick? Is it the table-cloth or objects-cloth friction? At first, I think it is objects-cloth friction since it's those objects that's affected. But, the force exerting on objects are just the friction force since we apply the force only to the cloth not the objects, right? If the only force exerting on objects are friction, I don't understand which force that the friction affects. I mean, in order to know the objects will move or not, we should know two forces (the friction and the force), right?
2. The objects stay on the table because it can't 'catch' the cloth, right? (objects move very slowly so it can't 'catch' the cloth) or, does the kinetic friction makes the objects move in opposite direction of the cloth??
Please help
I know that if the force exceeds the maximum value of static friction, the objects will stay on the table.
But, I still don't understand two things.
1. What static friction should be exceeded to do the trick? Is it the table-cloth or objects-cloth friction? At first, I think it is objects-cloth friction since it's those objects that's affected. But, the force exerting on objects are just the friction force since we apply the force only to the cloth not the objects, right? If the only force exerting on objects are friction, I don't understand which force that the friction affects. I mean, in order to know the objects will move or not, we should know two forces (the friction and the force), right?
2. The objects stay on the table because it can't 'catch' the cloth, right? (objects move very slowly so it can't 'catch' the cloth) or, does the kinetic friction makes the objects move in opposite direction of the cloth??
Please help