Albert Teen

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Hooke’s Law

Hooke’s Law

Hooke’s Law

In this lesson you will learn what Hooke's Law is, to describe the property of elasticity.

Some objects may stretch, compress or bend when you apply a force to them, then return to their original shape when the force is removed. Try to guess what we call these types of objects.

A spring is a good example of an elastic object. If you stretch a spring and it returns to its original shape and length, we say that it was elastically deformed.

If you continue to add force to a spring, eventually the spring will no longer return to its original shape and length. What might we call the type of deformation that the spring undergoes now?

Hooke's Law states that the extension of an elastic object is directly proportional to the force applied to it. By the way, it's called "Hooke's Law" because it was the scientist Robert Hooke who first stated this law of elasticity.

If the extension of a spring is $6\space cm$with a force of $10\space N$applied, what is the extension if $5\space N$ of force is applied?

Hooke's Law tells us that the extension of an elastic object is directly proportional to the force applied to it, but which factor other than force will influence the extension of a spring?

How easily a spring can be stretched or compressed is measured in Newtons per metre $(N/m)$ . We call this property the spring constant.

Answer TRUE or FALSE: The higher the spring constant, the more loose the spring.

When using the spring constant in calculations, the units used are Newtons per metre. This means you must always convert your extension measurements into metres. If you measured an extension of $5\space cm$ , what is this in metres?

The force applied to a spring is$2\space N$, the extension of the spring is$0.1\space m$, and the spring constant is$20\space N/m$. What is the formula that links force, extension and spring constant?

The formula for Hooke's law is written as$F=kx$. Try to guess which symbol represents the spring constant.

If a spring has a spring constant of $40\space N/m$ , and its extension is $15\space cm$ , how much force has been applied to cause the extension?

If the force applied to a spring is$4\space N$, and its extension is$4\space cm$, what is the spring constant? Remember to convert the extension to metres before using the formula.