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+ <h2>Solutions of Savchenko Problems in Physics</h2>
+ <p class="author">
+ Aliaksandr Melnichenka <br/>
+ October 2023
+ </p>
+ </header>
+
+ <h3 id="back-link"><a href="../#1.2">$\leftarrow$Back</a></h3>
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+ <h3> Statement </h3>
+ <p>
+ $1.2.7.$ The bus moves for $20$ seconds in a straight line to the stop, passing a distance of $310$ m. Its initial speed is $15$ $\frac{m}{s}$. Prove that the velocity of the bus changes in direction.
+ </p>
+
+ <h3>Solution</h3>
+ <p>
+ Since the bus comes to a complete stop at the end, the average speed is
+$$v_\text{average}=\frac{15+0}{2} \frac{m}{s}=7.5 \frac{m}{s}$$
+If there is an equal-accelerated motion, then the body must travel a path
+$$s = v_\text{average}\cdot t=150\text{ m}$$
+Whence it follows that the body has accelerated, but the motion is not equal-accelerated
+ </p>
+
+ <h4>Answer</h4>
+ <p>
+ The average velocity is greater than the initial velocity and the final velocity is zero.
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