Types of Motion Measurement: Definition, Methods, Examples

Motion is defined as the movement or change in the position of an object or body. When an object is not moving, it is said to be relatively at rest. Measurement is the comparison of an unknown quantity with a known fixed quantity. 

Also Read: Angular Speed

Key Terms: Motion, Measurement, Quantity, Standard Units, Cubit, SI Unit, Metric System, Rectilinear Motion, Circular Motion, Periodic Motion

---

Measurement of Motion

[Click Here for Sample Questions]

Measurement is defined as the fixed known quantity used to measure something. Different people may have different units of measurement which leads to confusion. For example, if you ask your tailor to give you a ribbon of the length of an arm, then there is no fixed unit of arm length as it depends on person to person. Hence, we need a fixed or standard unit of measurement to measure quantities accurately, to bring uniformity and to avoid misunderstandings.

Read Also: Uniform Motion, Wave Motion

---

Components

[Click Here for Sample Questions]

Measurement involves two basic components, i.e. Units and Numbers.

• Units - It is the known fixed quantity required for measurement.
• Number - It is the quantity of the number of units that the object contains.

Also Read:

---

Methods of Measurement

[Click Here for Sample Questions]

There are primarily two methods of taking measurement - the Conventional System of Measurement and the Standard System of Measurement.

• Conventional System of Measurement: This method provides an approximate measure of an object. It was developed in the early ages of The Indus Valley Civilization and is not a scientific method of measurement. Some examples of units in this measurement are Hand Span, Arm Length, Cubit, Footstep, etc. The most significant drawback of this method is that it is inconsistent as it varies from person to person since we all differ in height and size.
• Standard System of Measurement: Also known as the International System of Units, or simply, SI Unit, this method involves the use of standard units of measurement. It was created by the French in 1790 which they named as the metric system. Scientists from all over the world have since accepted it as the standard unit of measurement as it is comparatively consistent and does not vary from person to person. Examples of standard methods of measurement include the SI unit of distance which is metre(m).

Check Also: Force and Motion

---

Precautions While Taking Measurements

[Click Here for Sample Questions]

1. Always use an appropriate measurement tool or device for measuring. For example, when measuring a curved line or object, measuring scale is not the best tool as it might give a wrong measure/result. Therefore, in this case, we should use a measuring tape or a thread.
2. To use a thread for measurement, tie a knot at the beginning of the thread and stretch it across the object. Measure the length and then place the thread across a measuring scale to determine the measurement.
3. If on a scale, the mark ‘0’ is not visible clearly or the scale is broken from the either ends, then we should start the measurement from the next visible mark or any suitable mark/number (like the number ‘1’) and then continue the measurement from that number. The length or distance can be measured by applying the following formula.
4. Length = Final Value On The Scale - Initial Value Of The Scale
5. Always make sure that your eyes are correctly positioned while taking measurement. Different positions of the eyes produce different and incorrect results.Hence, your eyes should be positioned straight in front of the scale.

Read More: Wave Optics

---

Types of Motion of Bodies

[Click Here for Sample Questions]

A body is said to be in motion if its position changes over a period of time. Motion is classified into three types - Rectilinear Motion, Circular Motion, and Periodic Motion.

Rectilinear Motion 

When a body or an object moves in a straight motion or along a linear/straight line, it is called a rectilinear motion.Examples of rectilinear motion are launch of a rocket, movement of an elevator, car moving in a straight road,etc.

Circular Motion 

It is the type of motion in which the distance between the object from a particular fixed point remains same or constant. For example, the movement of the hands of a clock, rotation of Earth around the Sun, etc. It can also be called as Rotational motion if the object moves in a circular motion on its own axis such as in the case of spinning a top.

Periodic Motion 

The motion in which the object in motion returns to or attains its original position after a fixed or specific period of time and again repeats its motion is called periodic motion. Such motion is also known as a ‘to and fro’ motion. Examples- movement of a pendulum, a child riding on a swing, etc.

Read Further: Rolling Motion

---

Measurement of Distance with respect to Time

[Click Here for Sample Questions]

• Denoted as T.
• It can be calculated using the formula, Distance = Speed/Time
• Motion can be fast paced or slow paced depending upon the distance covered in a period of time. If more distance is covered in less time, it is a fast motion and if distance covered is less it is a slow motion.

Check Important Notes for Equations of Motion

---

Things to Remember

[Click Here for Sample Questions]

• Measurement consists of Unit and Number.
• Standard or SI Unit involves the metric system.

1 Metre (m) = 100 Centimetres(cm)

1 Centimetre = 10 Millimeters (mm)

1 Kilometres(km) = 1000 Metres

• Kilometre or km is used for measuring larger distances.
• Circular motion also includes rotational motion.
• Distance = Speed/Time

Read Also: Wave Nature of Electromagnetic Radiation

---