# Motion

Get Started. It's Free Motion ## 1. Velocity

### 1.1. Speed in a specific given direction

1.1.1. When you know an object is in motion and the direction it is heading to, you know its velocity.

1.1.2. Example: 50 km/h southward

## 3. Reference point

### 3.1. A place or object used for comparison to determine if something is in motion

3.1.1. Good reference points are ones that are stationary. If you choose reference points that are moving. it might give you a false sense of motion.

## 4. Measuring motion

### 4.1. Scientists use units of measurement to describe motion precisely

4.1.1. International System of Units (SI). The SI unit of length is meter (m).

4.1.1.1. For smaller lengths, the prefix deci-, centi- or milli- is added to meter. A decimeter is a tenth of a meter, a centimeter is a hundredth of a meter, and a millimeter is a thousandth of a meter.

4.1.1.2. For longer lengths, the prefix kilo- is added to meter. A meter is a thousandth of a kilometer.

## 5. Speed

### 5.1. Average Speed

5.1.1. The total distance divided by the total time

### 5.2. Instantaneous speed

5.2.1. The rate of an object moving at a specific time

### 5.3. Calculating Speed

5.3.1. The equation Speed = Distance / Time can be used to calculate speed, where the distance traveled by the object is divided by total amount of time taken.

## 6. Slope

### 6.2. Calculating Slopes

6.2.1. Use the formula Slope= Rise / Run

## 7. Graphing motion

### 7.1. Graphing general motion

7.1.1. Distance-versus-time graph

7.1.1.1. These graphs can be used for general motion and acceleration. Time is the x-axis and distance is the y-axis. The slope represents the rate of speed. A straight line represents a constant speed while a curved line represents constant acceleration.

### 7.2. Graphing acceleration

7.2.1. Speed-versus-time graph

7.2.1.1. In these graphs, speed is the y-axis and time is the x-axis. A straight line in these graphs represent constant acceleration.

## 8. Acceleration

### 8.1. The rate at which velocity changes. Acceleration can occur in 3 ways

8.1.1. Increase in Speed

8.1.2. Decrease in Speed

8.1.2.1. Also known as negative acceleration, or deceleration

8.1.3. Change in Direction

8.1.3.1. Objects that changes direction accelerates. An object moving in a circular motion is continuously accelerating.

### 8.2. Calculating acceleration

8.2.1. The formula above is used to calculate the acceleration of an object in a straight line

8.2.1.1. The SI unit of acceleration is m/s^2 (meters per second squared)