### Concept Items

### 3.1 Acceleration

How can you use the definition of acceleration to explain the units in which acceleration is measured?

- Acceleration is the rate of change of velocity. Therefore, its unit is m/s
^{2}. - Acceleration is the rate of change of displacement. Therefore, its unit is m/s.
- Acceleration is the rate of change of velocity. Therefore, its unit is m
^{2}/s. - Acceleration is the rate of change of displacement. Therefore, its unit is m
^{2}/s.

- ${\text{m}}^{2}\text{/s}$
- ${\text{cm}}^{2}\text{/s}$
- ${\text{m/s}}^{2}$
- ${\text{cm/s}}^{2}$

- The car is accelerating because the magnitude as well as the direction of velocity is changing.
- The car is accelerating because the magnitude of velocity is changing.
- The car is accelerating because the direction of velocity is changing.
- The car is accelerating because neither the magnitude nor the direction of velocity is changing.

### 3.2 Representing Acceleration with Equations and Graphs

A student calculated the final velocity of a train that decelerated from 30.5 m/s and got an answer of âˆ’43.34 m/s. Which of the following might indicate that he made a mistake in his calculation?

- The sign of the final velocity is wrong.
- The magnitude of the answer is too small.
- There are too few significant digits in the answer.
- The units in the initial velocity are incorrect.

Create your own kinematics problem. Then, create a flow chart showing the steps someone would need to take to solve the problem.

- Acceleration
- Distance
- Displacement
- Force

- $v={v}_{0}+at$
- $v={v}_{0}\xe2\u02c6\u2019at$
- ${v}^{2}={{v}_{0}}^{2}+at$
- ${v}^{2}={{v}_{0}}^{2}\xe2\u02c6\u2019at$