Motion

This course is a part of Class 9 Physics (India), a 3-course Topic series from Khan Academy.

Motion is all around us, from moving cars to flying aeroplanes. Motion can have different features like speed, direction, acceleration, etc. In this chapter, we will understand these features in detail and see how it can help us predict the future of these moving things.

This course contains 9 segments:

Distance and displacement

When someone asks how 'far' did something travel, there are two answers based on how you interpret this question. One is distance, another is displacement. Let's learn what these things are.

Average speed and average velocity

One way to answer 'how fast something is moving' is by calculating average speed or average velocity. What's the difference you ask? In this lesson that's exactly what we will explore.

Instantaneous speed and velocity

In most cases, when we use the word speed, we are not talking about average speed, we are talking about speed at a particular instant of time. In this lesson we will understand this notion of 'instant' speed and velocity.

Acceleration

A race car not only has a very high top speed, but it can also 'pick up' speed very quickly. This concept of 'picking up' speed is called acceleration in physics. In this lesson, we will explore this in detail.

Position time graphs

One of the best ways to depict motion is by graphing. In this lesson, let's explore the position-time graphs.

Velocity time graphs

Velocity time graphs are super important. Using this one can figure out acceleration and displacements. Whoa.. how do we do that? That's exactly what we learn here!

Deriving equations of motion

When things are traveling with constant acceleration, we can derive simple relationships between velocities, acceleration, displacements, and time. Some call these, the SUVAT relations. Let's derive them.

Problem solving using kinematic equations

Sometimes it's hard to figure out which SUVAT equation to use in which case. In this lesson, we will learn how to choose the equations by gathering data and solving problems.

Uniform circular motion

Circular motion is everywhere, from electrons going around the nucleus, all the way to planets around the sun. In this lesson, we will introduce the 'uniform circular motion'.