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Bukhovtsev-et-al-Problems-in-Elementary-Physics

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MECHANICS<br />

181<br />

Hence (see Problem 62).<br />

.r 2l<br />

't= V a (cos a.-k s<strong>in</strong> a)<br />

If k ~ cot a, the bead will not move with respect to the rod, and<br />

of friction is rna cos a..<br />

the force<br />

64. The equations of motion of the block and the body have the form:<br />

ma=f (1)<br />

Mb::xF-f (2)<br />

where f Is the force of friction; a and b are accelerations.<br />

L<strong>et</strong> us assume that there is no slid<strong>in</strong>g, then a=b. The acceleration and<br />

the force of friction can be found from the equations of motion. The force<br />

of friction is f=m M:m' For the body not to slide, the force of friction<br />

should satisfy the <strong>in</strong>equ<strong>al</strong>ity f

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