Laws of Motion Class 9th Science | Maharashtra Board | CBSE | ONESHOT | Shubham Jha

Shubham Jha2 minutes read

The first chapter of Class Ninth Maharashtra State Board Science covers motion, displacement, velocity, acceleration, and related concepts. Various examples and scenarios are used to explain uniform and non-uniform motion, as well as the importance of direction and velocity in kinematic equations. Understanding Newton's laws of motion, momentum, and forces play a significant role in comprehending motion and its various applications in physics.

Insights

  • Motion is defined as a change in position with respect to the surroundings, with examples like a bird in flight or a moving car. Rest is the absence of motion, and motion can be uniform or non-uniform based on speed variations.
  • Displacement is the actual distance traveled, while displacement is the shortest path possible, emphasizing direction. Speed is distance over time, while velocity includes direction. Acceleration is the rate of change of velocity over time, with positive, negative, or zero values.
  • Newton's laws of motion, including the relationship between force and acceleration, action and reaction forces, and the conservation of momentum, are fundamental in understanding motion. Inertia resists changes in motion, and momentum depends on mass and velocity, with conservation before and after collisions.

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Recent questions

  • What is motion?

    Change in position with respect to surroundings.

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Summary

00:00

Motion Concepts in Class Ninth Science

  • The first chapter of science for Class Ninth Maharashtra State Board is about the loss of motion.
  • The chapter details motion, distance, displacement, acceleration, neutral loss of motion, and related questions.
  • The chapter content is usually outlined at the beginning of the chapter in a box.
  • Motion is defined as a change in position with respect to the surroundings.
  • Examples of motion include the flight of a bird, a moving car, and flowing water in a river.
  • Rest is defined as the absence of motion, where an object maintains its position.
  • Motion is a relative concept, depending on the observer's perspective.
  • Uniform motion involves equal distances covered in equal intervals of time.
  • Non-uniform motion involves unequal distances covered in unequal intervals of time.
  • Understanding motion concepts requires considering the observer's viewpoint and the relative nature of motion.

12:08

"Speed, Traffic, and Motion in Travel"

  • Traveling at RK speed per kilometer, traffic can slow you down to 8 km.
  • Clear paths allow for faster travel, taking less time to cover distances.
  • Understanding time differences in traffic scenarios is crucial for accurate travel estimates.
  • Amar, Akbar, and Anthony walk at different speeds, covering varying distances.
  • Uniform motion involves consistent speed and equal intervals of distance.
  • Motion can be uniform or non-uniform based on speed variations.
  • The motion of a clock's hand exemplifies uniform motion.
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24:30

Understanding Displacement, Speed, and Acceleration in Physics

  • Displacement refers to the actual distance traveled, while displacement is the shortest path possible.
  • Displacement is a vector quantity, emphasizing the importance of direction in determining the shortest path.
  • Displacement is calculated as the minimum distance between starting and ending points, representing the shortest route.
  • Displacement is zero when the starting and ending points are the same, indicating no movement.
  • Speed is defined as the distance covered by an object in a unit of time, while velocity includes direction.
  • Average speed is calculated by dividing the total distance traveled by the total time taken.
  • Acceleration is the rate of change of velocity over time, represented by the formula (final velocity - initial velocity) / time.
  • Acceleration can be positive, negative, or zero, depending on whether the speed increases, decreases, or remains constant over time.
  • Uniform circular motion involves a body moving along the circumference of a circle at a constant speed.
  • In uniform circular motion, the speed remains constant, but the direction changes continuously as the body moves around the circle.

38:48

Kinematic Equations: Pentagon, Graphs, and Motion

  • To reach the starting point after multiple rounds, one must go to the Pentagon and circle around it 5 times.
  • Increasing the number results in a hexagon formation, requiring 6 rounds to complete.
  • In uniform circular motion, the direction changes continuously due to infinite points, leading to acceleration.
  • Graphical representation of motion involves plotting distance-time and velocity-time graphs.
  • The distance-time graph for uniform motion results in a straight line, indicating constant speed.
  • For non-uniform motion, the graph is not a straight line, showcasing varying speed.
  • The velocity-time graph provides information on acceleration, while the distance-time graph reveals speed.
  • Understanding the relationship between velocity, displacement, and time is crucial for solving kinematic equations.
  • The three kinematic equations are V = U + at, S = Ut + 1/2 at², and v² = u² + 2as.
  • A mnemonic device "Water Park, Shubham, Half Ata Square" aids in recalling the equations for solving numerical exercises.

51:41

Calculating Values and Forces in Motion

  • The value of "you" and "we" are equal, leading to a calculation to find the value of "you."
  • The equation 2 + 4 * 3 is solved to get the answer of 12.
  • The velocity is denoted as "m per second" due to the mention of velocity.
  • Another equation is presented to find the value of "u" as "B - 80."
  • The value of "u" is calculated as 20 based on the given information.
  • A calculation is done to find the answer of 15 based on the equation S = ut + 1/2 at².
  • The distance covered by an airplane on a runway is calculated using the formula ut + 1/2 at².
  • The final velocity of a kangaroo jumping vertically is calculated as 7m per second.
  • The acceleration and distance traveled by an object are calculated using the formula v² = u² + 2as.
  • The concept of force, motion, and types of forces are explained, emphasizing balanced and unbalanced forces.

01:05:35

"Mass, Momentum, and Newton's Laws Explained"

  • Mass of a body determines its meaning and significance.
  • The number of peas inside a body is crucial.
  • The force applied on a stone depends on its mass.
  • An experiment involving a coin, glass, and seat is conducted.
  • Inertia is explained as the tendency of a body to resist change in motion.
  • Sir Isaac Newton's fundamentals of motion are discussed.
  • Momentum is defined as the product of mass and velocity.
  • Momentum depends on mass and velocity, impacting the force.
  • Newton's second law of motion emphasizes the relationship between force and acceleration.
  • Newton's third law of motion highlights the concept of action and reaction forces.

01:21:27

Newton's Third Law and Momentum Conservation

  • Third action is reaction, both signs will be Mental real walk, feet walk, time internal means one will be with the other but both are opposite.
  • The body will be okay because the line is equal and opposite, never consult other on different body things.
  • 10 Newton's force is going positive on one side and negative 10 Newton's force on the other side.
  • Positive and negative forces cannot cancel out on different bodies.
  • Trumping is going on, action on different bodies, reaction force is equal and opposite.
  • Newton's Third Law of Motion concludes with the Conservation of Momentum theory.
  • Momentum is conserved before and after collision, total momentum remains the same.
  • Force is equal to mass times acceleration, momentum equals mass times velocity.
  • A numerical question involves finding momentum given mass and velocity values.
  • Another numerical question involves calculating final velocities after a collision based on mass and initial velocities.
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