Confused between scalar and vector? What is the difference between distance and displacement? How are speed and velocity different from each other? This seemingly easy terms always confuse us. Before we jump right into the technicalities of motion, here are some basic parameters of motion that will help you understand the topic well!

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## Motion

The change in the position of the object with respect to time is called the motion of that object. The change in motion is based on the reference point of an individual. Let’s take an example of the 2 cars (A and B) moving at a constant speed that you observe from your school window.

From your reference point, the cars are in motion because they are constantly moving. Although, from the reference point of the car A, car B is not in motion since it has the same speed as car A. But you on the other hand, for car A, will be in motion because of the constant change in your positionÂ from the reference point of car A

## Parameters of Motion

**Scalar Quantity**

These quantities only have a magnitude(size) and no directions. Examples of such quantities are speed, mass, distance, volume and many others.

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**Vector Quantity**

These quantities have both magnitude and direction. So change in any one of the two will change the value of the vector quantities. Examples of vector quantities areÂ velocity, acceleration, force, displacement and many more.

**Distance**

The length of the total path travelled by the body is the distance travelled by the body. It is the scalar quantity. Mostly measured in m(meters).

**Displacement**

The length of the shortest path travelled by the body from point A to B is the displacement. It is the scalar quantity. Mostly measured in m(meters).

**Speed**

The distance travelledÂ by the body per unit time is the speed of the body. It is a scalar quantity. Speed is given by the formula, speed=distance/time, Measured in m/s.

**Uniform speed**

If a body travels equal distance at equal intervals of time, the body is said to be moving at a uniform speed.

**Non-Uniform speed**

If the speed of the body keeps changing throughout the body is said toÂ be moving at a non-uniform speed. The average speed of the body= total distance travelled/total time takenÂ to travel the distance.

### Velocity

The displacement of a body from point A to B per unit time is the velocity. It is a vector quantity, which means it has both magnitude and direction. Velocity is given by the formula, Velocity=displacement/time, Measured in m/s.

**Uniform velocity**

If a body travels equal distance at equal intervals of time in a straight line the body is said to be moving at a uniform velocity.

**Non-Uniform Velocity**

If a body travels unequal distance at equal intervals of time in a straight line the body is said to be moving at a non-uniform velocity. The average velocity = total displacement/total time taken.

### Acceleration

If a body changes its velocity with time, it is said to be accelerated. Acceleration is defined as the rate of change of velocity with respect to time. Its unit is m/s^{2}.

**You can download Motion Cheat Sheet by clicking on the download button below**

## Solved Examples on Parameters of Motion

Question:Â Unit of acceleration is

- m/s
- ms
- m/s
^{2} - none of these

Solution: Option C. Acceleration = dv/dt. Unit of ‘v’ is m/s and ‘t’ is s. Therefore, the unit of acceleration isÂ m/s^{2}.

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