Edit to “Solution”
en/1.2.7.md
+1 −1
| ### Statement | |||
| $1.2.7.$ The bus moves for $20$ seconds in a straight line to the stop, passing a distance of $310 \text{ m}$. Its initial speed is $15~\mathrm{\frac{m}{s}}$. Prove that the velocity of the bus changes in direction. | |||
| @@ -5,7 +5,7 @@Statement | |||
| ### Solution | |||
| Since the bus comes to a complete stop at the end, the average speed is | |||
| − | |||
| + | test | ||
| $$ | |||
| v_\text{average}=\frac{15+0}{2}~ \mathrm{\frac{m}{s}}=7.5~ \mathrm{\frac{m}{s}} | |||
| $$ | |||
| 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 | |||
| #### Answer | |||
| The average velocity is greater than the initial velocity and the final velocity is zero. | |||
| unchanged lines 12 | |||
| ### Statement | ### Statement | ||
| $1.2.7.$ The bus moves for $20$ seconds in a straight line to the stop, passing a distance of $310 \text{ m}$. Its initial speed is $15~\mathrm{\frac{m}{s}}$. Prove that the velocity of the bus changes in direction. | $1.2.7.$ The bus moves for $20$ seconds in a straight line to the stop, passing a distance of $310 \text{ m}$. Its initial speed is $15~\mathrm{\frac{m}{s}}$. Prove that the velocity of the bus changes in direction. | ||
| @@ -5,7 +5,7 @@Statement | |||
| ### Solution | ### Solution | ||
| Since the bus comes to a complete stop at the end, the average speed is | Since the bus comes to a complete stop at the end, the average speed is | ||
| test | |||
| $$ | $$ | ||
| v_\text{average}=\frac{15+0}{2}~ \mathrm{\frac{m}{s}}=7.5~ \mathrm{\frac{m}{s}} | v_\text{average}=\frac{15+0}{2}~ \mathrm{\frac{m}{s}}=7.5~ \mathrm{\frac{m}{s}} | ||
| $$ | $$ | ||
| If there is an equal-accelerated motion, then the body must travel a path | If there is an equal-accelerated motion, then the body must travel a path | ||
| $$ | $$ | ||
| s = v_\text{average}\cdot t=150\text{ m} | s = v_\text{average}\cdot t=150\text{ m} | ||
| $$ | $$ | ||
| Whence it follows that the body has accelerated, but the motion is not equal-accelerated | Whence it follows that the body has accelerated, but the motion is not equal-accelerated | ||
| #### Answer | #### Answer | ||
| The average velocity is greater than the initial velocity and the final velocity is zero. | The average velocity is greater than the initial velocity and the final velocity is zero. | ||
| unchanged lines 12 | |||