Motion and Time Class 7 Notes CBSE Science Chapter 9 (Free PDF Download)

Motion

• The movement of an object or the tendency of an object to move from its place with respect to time is called motion 

• For example Movement of the pendulum of a clock is a motion, falling of leaves from trees is a motion etc.

There are two types of motions 

1. Uniform Motion: If an object moves in a straight line at a constant speed i.e., speed is not changing over time, then the motion is uniform motion.

2. Non-Uniform Motion: If an object moves in a straight line and the speed of an object changes over time, then the motion is a non-uniform motion.

Speed

• The distance covered by an object per unit time is called speed. Thus,

$S=\dfrac{D}{T}$  where $S$ represent the speed of an object, $D$ represent the distance covered by an object and $T$ represent the time taken by the object.

• SI unit of speed is $m/s$.

Measurement of Time

• In earlier periods, the shadow of objects cast by the sun was used to measure time.

• Simple Pendulum: It is a type of clock used to measure time and is the best example of periodic motion.

• Periodic or oscillatory motion is the to and fro movement of an object.

• Oscillation: The process of moving back and forth.

• The time taken by the pendulum to complete one complete oscillation is called the time period.

• The basic or SI unit of time is seconds denoted by $s$

Measuring Speed:

• Speedometer: It is a device used to measure the speed of a vehicle is $Km/hr$ 

• Odometer: It is a device used to measure the distance covered by a vehicle.

Distance-Time Graph 

• It is used to study the motion of an object. 

• The distance is represented on the Y-axis and time is represented on the X-axis.

• The motion is uniform when the distance-time graph is a straight line.

• If the distance-time graph is moving upwards then the speed of the object is increasing. 

•  If the distance-time graph is moving downwards then the speed of an object is decreasing

• The object is said to be at rest if the distance-time graph is parallel to the X-axis.

• The object's speed is determined by the slope of the distance-time graph.

• If there is a curve in the distance-time graph then the speed of the object is changing.

Class 7 Science Chapter Motion and Time notes PDF

These notes of Class 7 Science Motion and Time have been well-written covering all the important points of the chapter. Students need to download these notes and then refer to them when they wish to. Students get to study at their comfort and pace. The PDF version of the notes on Motion and Time Class 7 can either be referred to on a device, or one can take a hardcopy of the same and go through it. The notes have all the points covered, so instead of taking the trouble of making their notes, all that the student has to do now is to download the notes from this site and go through it.

Time and Motion Class 7 Notes Revision 

Our revision CBSE Class 7 Science Chapter 9 Motion and Time notes cover the details of the chapter that lets students refer to the notes before an exam.

Motion

Distance is the absolute path that is covered by an object in a given time interval. Displacement is the shortest distance that is covered by the object in a given time interval. Distance is calculated as the product of speed and time. The distance is represented in meters, kilometres. 

An object stays in motion if its position changes concerning time, like when a car moves on the road. An object is at rest if it does not change its position concerning time. Like when a person stands on the ground.

As a standard, distance is measured in meters, the unit of time in seconds, and the unit of speed is meter/second.

The Types of Motion

Motion is of three types. These are rectilinear motion or translatory motion, circular motion, and period or oscillatory motion.

The rectilinear or translatory motion is where the body moves in a straight line without it changing its direction. Like when a car moves on a straight road.

A circular motion is where the body moves in a circular shape about a fixed point and on a fixed radius, like the motion of the planets around the sun.

A period or oscillatory motion is when the body's motion repeats after a fixed time interval. Like, the to and fro movement of the pendulum.

A periodic or an oscillatory motion is where the motion of the body gets repeated after a fixed interval of time. This is like the pendulum moving. The car's motion in a circular path of the motion of the planet around the sun.

The Oscillation of a Simple Pendulum

When the bob of the pendulum moves from A to B and then back to A again, it is considered one complete oscillation. The time period is the total time taken by the pendulum to complete one oscillation.

Time and Speed

Speed or the average speed is the total distance that the object covers in a particular time interval. Speed is the distance travelled divided by the time taken. Speed is calculated as the distance travelled to the time taken. The unit of speed is measured in meters per second or kilometres per hour.

A motion could be uniform or non-uniform. A uniform motion is when the object moves along in a straight line, and with constant speed, the object is in a uniform motion. Like when a car moves in a straight line with constant speed. A non-uniform motion is when an object moves on a straight line, and it changes its speed with time. Like when a train is in motion.

Time is usually measured in sends, hours, or minutes. The period is the total amount of time taken by an object to complete one full oscillation.

Why are Revision Notes for Class 7 Chapter 9 - Motion and Time Important?

• Provides quick, clear summaries of key concepts.

• Simplifies complex topics for better understanding.

• Efficient tool for last-minute exam prep.

• Enhances retention of crucial information.

• Supports effective exam preparation with key points and tips.

• Saves time by consolidating information.

• Prioritizes important topics and questions.

• Offers practical examples for real-world connections.

• Boosts student confidence for exams.

Conclusion

The notes for CBSE Class 7 provide a clear and thorough grasp of key concepts in Science - Motion and Time. Students benefit from insights into the properties and characteristics of motion and the measurement of time. The well-organized format supports efficient revision, aiding in better retention. Practical examples, like understanding how objects move and measuring time, enrich the understanding of the subject. These notes are essential for building a strong foundation in the exciting world of motion and time and excelling academically. They've proven invaluable in helping students succeed in their studies.