Speed is a fundamental concept in physics that refers to how fast an object is moving. It is a scalar quantity and is defined as the distance traveled per unit of time. The formula for calculating speed is:

**Speed = Distance / Time**

The SI unit of speed is meters per second (m/s). However, other common units of speed include kilometers per hour (km/h) and miles per hour (mph).

There are different types of speed that are commonly used in physics, including:

**Instantaneous Speed:**The speed of an object at a specific instant in time.**Average Speed:**The total distance traveled divided by the total time taken.**Uniform Speed:**When an object covers equal distances in equal intervals of time.**Variable Speed:**When an object's speed changes over time.

To calculate the speed of an object, you need to know the distance it has traveled and the time it took to travel that distance. Here's an example:

If a car travels 100 kilometers in 2 hours, its speed can be calculated as:

**Speed = 100 km / 2 hours = 50 km/h**

When studying the concept of speed in physics, it's important to understand the following key points:

- Understand the definition of speed and its formula.
- Be able to convert between different units of speed (m/s to km/h, etc.).
- Recognize the difference between instantaneous and average speed.
- Practice calculating speed using given distance and time values.
- Understand the concept of uniform and variable speed, and how to identify each.

Mastering the concept of speed is crucial for understanding motion and dynamics in physics. It forms the basis for more advanced topics such as velocity, acceleration, and kinematics.

PHYSICAL SCIENCE (NGSS)

Energy

Students who demonstrate understanding can:

Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.

Develop and use models to illustrate that energy at the macroscopic scale can be accounted for as either motions of particles or energy stored in fields.