$1.2.7.$ 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.
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
The average velocity is greater than the initial velocity and the final velocity is zero.