Mechanism that causes tension and normal force?

[InertialRef]

Homework Statement

What is a mechanism that might cause a rubber band or a string to develop tension in response to a force that you apply?

What mechanism explains how walls and tables exert normal forces without bending noticeably?

Homework Equations

None, since this is a conceptual question.

The Attempt at a Solution

I initially wrote down the elasticity of the material used for the rubber band as well as the wall. However, I'm not completely sure my reasoning is correct. Elasticity only affects how much the object would stretch when a force is applied, not the tension force that is developed in response. Even if you had two rubber bands, one more stiffer than the other, if you applied the same amount of force on them, wouldn't they exert the same amount of tension back? In that case then, wouldn't it be the magnitude of the force exerted upon the rubber band or wall that is the mechanism?

 

[CWatters]

I think they are asking for a deeper explanation. For example what stops a rubber band (or anything else) simply falling apart when a force is applied? What keeps the material together?

 

[InertialRef]

I think they are asking for a deeper explanation. For example what stops a rubber band (or anything else) simply falling apart when a force is applied? What keeps the material together?

I'm not completely sure about that, since it's a first year physics course. But if they were asking for a deeper explanation, wouldn't that involve discussing the types of bonds that make up the material?

 

[CWatters]

May not need to explain the different type of bonds, just that bonds are involved?

The question about walls and tables asks why they don't bend so perhaps this is also a question about tension rather than compression? Otherwise for compression I think you have to talk about the Pauli exclusion principle? But have you covered that yet?

 

[Nickie]

The mechanism that causes tension in a rubber band or string when a force is applied is the stretching of the material. When a force is applied, the material is pulled in opposite directions, causing it to stretch and creating tension in the material. This tension is what allows the rubber band or string to resist the force and maintain its shape.

Similarly, the mechanism that explains how walls and tables exert normal forces without bending noticeably is the compression of the material. When an object is placed on a table or pushed against a wall, the material of the table or wall compresses slightly in response to the force. This compression creates a normal force that acts perpendicular to the surface of the material, providing support and preventing the object from falling or bending the surface noticeably.

In both cases, the elasticity of the material plays a role in determining the amount of tension or normal force that is exerted. A stiffer material may require more force to stretch or compress, resulting in a higher tension or normal force. However, the magnitude of the force applied is also a determining factor in the amount of tension or normal force that is developed. So, the combination of elasticity and force determine the mechanism behind tension and normal force in these scenarios.