Types of Motion Measurement 

1.0Introduction to Motion and Its Measurement

Physics deals with the study of motion of objects and the forces acting on them. Motion is the change in position of an object with respect to time. For JEE students, motion and its measurement form the foundation of mechanics, helping solve problems related to displacement, velocity, acceleration, and force.

The measurement of motion is essential to understand how fast an object moves, in what direction, and how forces affect it. It allows us to analyze both everyday motions (like vehicles moving on roads) and cosmic motions (like planets orbiting stars).

2.0What is Motion Measurement in Physics?

Rest

If position does not change with time, then it is at rest.

Motion

If the position of particle changes with time, then it is called in motion.

Motion measurement in physics refers to the quantitative study of displacement, velocity, and acceleration of objects as they move.

• It involves parameters such as distance, displacement, speed, velocity, and acceleration.
• Motion can be measured using kinematic equations and experimental tools like photogates, radar guns, and high-speed cameras.

In JEE-level physics, motion measurement is primarily done using kinematics equations and understanding the difference between uniform and non-uniform motion.

3.0Types of Motion in Physics

Motion can be classified into different types based on the path taken by the object, the nature of its motion, and periodicity. Below are the main types of motion that JEE students must master.

1-D Motion

• If position changes with time with respect to frame of reference along a straight line, motion is one
• dimensional (1-D) or straight-line motion or rectilinear motion.
• Examples: Motion of Train Along Straight Track , A Ball Projected Upward.

2-D Motion

• If position changes in a plane with time with respect to frame of reference then motion is 2-D.
• Examples: Projectile Motion

3-D Motion

• If position changes in space with time with respect to frame of reference, motion is 3-D or motion in space.
• Examples: Motions of Kite

(f) Rectilinear and Curvilinear Motion

• Rectilinear motion: Motion along a straight line.
• Curvilinear motion: Motion along a curved path.

Understanding these types of motion is crucial since JEE often includes conceptual and numerical problems based on them.

4.0Methods of Motion Measurement

Motion can be measured in various ways depending on the type of motion:

• Displacement and Distance Measurement: Using rulers, measuring tapes, and coordinate geometry.
• Velocity Measurement: Using time taken for displacement or devices like speedometers.
• Acceleration Measurement: Using change in velocity with time.
• Graphical Methods: Displacement-time and velocity-time graphs.
• Equations of Motion: Standard kinematic equations applied to uniform acceleration cases.

5.0Equations Used in Motion Measurement

The equations of uniformly accelerated motion are the backbone of motion measurement in physics:

$$\begin{gathered} 1.v=u+at \\ 2.s=ut+\frac{1}{2}a{t}^2 \\ 3.v^2=u^2+2as \end{gathered}$$

Where:

u = initial velocity
v = final velocity
a = acceleration
s = displacement
t = time

These formulas allow accurate measurement of displacement, velocity, and acceleration in both theoretical and experimental physics.

6.0Motion Measurement in Uniform and Non-Uniform Motion

• Uniform Motion: When an object covers equal distances in equal time intervals. Measurement involves constant velocity equations.
• Non-Uniform Motion: When an object covers unequal distances in equal time intervals. Measurement requires using acceleration and velocity equations.

For example:

• A car moving at a constant speed of 60 km/h → uniform motion.
• A car accelerating from rest to 60 km/h → non-uniform motion.

7.0Motion Measurement Examples

Some motion measurement examples important for JEE include:

• Measuring the time period of a pendulum using a stopwatch.
• Calculating the displacement of a train moving with uniform acceleration.
• Measuring the angular velocity of a rotating fan.
• Analyzing projectile motion using horizontal and vertical components.

Each of these examples demonstrates how physics connects real-world motion with precise mathematical measurement.

8.0Applications of Motion Measurement

Motion measurement is applied in:

• Projectile Motion: Splitting into horizontal and vertical components.
• Satellite Motion: Measuring orbital velocity and period.
• Kinematics Graphs: Understanding displacement-time and velocity-time relationships.
• Practical Experiments: Using photogates, motion sensors, and ticker timers.

9.0Solved Problems on Motion Measurement

Problem 1: A car accelerates uniformly from rest at $2m/s^2$. Find its displacement in 5 s.

Solution:

$$\begin{gathered} s=ut+\frac{1}{2}a{t}^2 \\ s=0+\frac{1}{2}\times 2\times 25=25\text{m} \end{gathered}$$

Problem 2: A body moving with velocity 10 m/s is uniformly accelerated at $2m/s^2$. Find its velocity after 8 s.

Solution:

$v=u+at=10+2\times 8=26\text{m/s}$

Problem 3: A stone is dropped from a height of 80 m. Calculate the time taken to reach the ground.

Solution:

$$\begin{gathered} s=\frac{1}{2}g{t}^2 \\ 80=\frac{1}{2}\times 9.8\times t^2 \\ {t}^2=\frac{160}{9.8}\approx 16.3 \\ t\approx 4.04\text{s} \end{gathered}$$