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+ <meta name="description" content="Why is it easier to pull out a nail that is firmly embedded in a log if you simultaneously rotate it around its own axis when pulling it out?">
+ <meta name="author" content="Aliaksandr Melnichenka">
+ <meta name="date" content="2023-10" scheme="YYYY-MM">
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+ <span><img src = "../../img/book.png"><span><span>Savchenko Solutions</span>
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+ Solutions of Savchenko Problems in Physics <br>
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+ <h3 id="back-link"><a href="../../#2.1">$\leftarrow$Back</a></h3>
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+ <h3> Statement </h3>
+ <p>
+ $2.1.42.$ Why is it easier to pull out a nail that is firmly embedded in a log if you simultaneously rotate it around its own axis when pulling it out?
+ </p>
+
+ <h3>Solution</h3>
+ <p>
+ <center>
+<figure>
+<img src="https://savchenkosolutions.com/2/2.1.42/sol.jpg"
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+<figcaption>
+Forces acting on a driven nail
+</figcaption>
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+<p>
+The sliding friction force acts along the line of motion in the opposite direction; its magnitude is determined only by the coefficient of friction of the surfaces (i.e. for a given nail it is conditionally constant in magnitude and does not depend on the method of motion).
+</p>
+<p>
+If you pull it straight, you need to apply a large force along the axis of the nail. And if you rotate it, the friction force vector rotates from the axis of the nail, decomposing into two perpendicular forces: a small axial force and a large radial force. A large radial force is overcome with a lever (the length of the pliers handles is much greater than the diameter of the nail). A small axial component remains, which is easy to overcome.
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