Answer :
Answer:
Explanation:Certainly! Here's a brief summary of chapters 3 and 4 from the class 9 physics book on "Moments":
**Chapter 3: Moments**
- **Concept of Moment:** Moment of a force about a point is defined as the product of the force and the perpendicular distance from the point to the line of action of the force.
- **Calculating Moments:** Moment (or torque) = Force × Perpendicular Distance.
- **Balanced and Unbalanced Moments:** If the sum of clockwise moments equals the sum of anticlockwise moments about a point, the object is in equilibrium.
- **Applications:** Understanding moments is crucial in designing structures like bridges, levers, and simple machines.
**Chapter 4: Turning Effect of Forces**
- **Turning Effect:** When a force acts on a body, it tends to rotate the body about a pivot point.
- **Moment of a Couple:** Two equal and opposite forces acting on a body at different points create a couple. The moment of a couple is given by Force × Distance between the forces.
- **Conditions for Equilibrium:** For a body to be in equilibrium under the action of forces and couples, the algebraic sum of moments about any point must be zero.
- **Applications:** Practical examples include door hinges, wheelbarrows, and seesaws, where turning effects of forces are utilized.
These chapters lay the foundation for understanding how forces create rotational effects and how these effects are balanced in various physical systems and structures.
Answer:
summary of chapter 3 and 4 moments class 9th
Explanation:
Mahendra narrated a story to ganesg about his cook Iswaran ,who was a marvelous storyteller. Mahendra himself was a junior supervisor responsible for keeping an eye on the work sites .he did not find difficult to adjust to odd conditions .Iswaran followed him uncomplainingly to wherever he was posted and did all his chores for him . He could weave endless stories and anecdotes. Iswaran loved reading popular Tamil thrillers,which greatly influenced his descriptions and the way he built up suspense. Iswaran often left a story hanging. Iswaran told stories everyday in his inimitable style and compensated for the absence a TV in Mahendra's living quarters. One day ,after a delicious dinner prepared specially for an on auspicious day to feed spirits of ancestors , Iswaran began by telling Mahendra that the factory area they were working had once been a burial ground. In the morning,Iswaran told him he knew that the previous night Mahendra had seen the ghost of a woman with a foetus in her arms . Iswaran had heard the moaning from his room. Mahendra handed in his papers ,resolving to leave the haunted place the very next day.
chapter4
This story talks about the Kingdom of Fools. The kingdom is ruled by a foolish king and he has a foolish minister. In order to create some change and make a Kingdom different from others, the king and his minister decide to complete all the day's work at night and vice versa.