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Chapter Analysis
Intermediate14 pages • EnglishQuick Summary
This chapter explains the core concepts of force and motion, exploring Newton's three laws of motion and the principle of inertia. The chapter illustrates how forces impact momentum and acceleration using real-life examples like cricket and car motion, and it includes mathematical formulations to further explain these phenomena. The interaction of action and reaction forces is also covered, providing a foundation for understanding complex physical systems.
Key Topics
- •Newton's First Law of Motion
- •Inertia and Mass
- •Newton's Second Law of Motion
- •Momentum
- •Newton's Third Law of Motion
- •Balanced and Unbalanced Forces
- •Applications of Laws of Motion
Learning Objectives
- ✓Understand and explain Newton's three laws of motion.
- ✓Apply the concept of inertia to real-world situations.
- ✓Calculate forces acting on an object using mathematical formulations.
- ✓Explain the interaction between action and reaction forces in various contexts.
- ✓Discuss the effects of balanced and unbalanced forces on an object's motion.
- ✓Analyze momentum and its relation to force and velocity.
Questions in Chapter
An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on
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When a carpet is beaten with a stick, dust comes out of it, Explain.
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Why is it advised to tie any luggage kept on the roof of a bus with a rope?
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A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because
Answer: Because there is a force on the ball opposing the motion of the ball.
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A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 tonnes.
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A stone of 1 kg is thrown with a velocity of 20 m s–1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?
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An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 m s–2?
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Additional Practice Questions
Explain the concept of inertia with a real-world example not covered in the textbook.
mediumAnswer: Inertia is the resistance of any physical object to a change in its state of motion or rest. For example, passengers in a car tend to move forward when the car suddenly stops. This happens because the passengers continue in their state of motion even when the car is decelerating.
How does Newton's third law of motion apply to a rocket launch?
mediumAnswer: According to Newton's third law, every action has an equal and opposite reaction. In a rocket launch, the engine burns fuel and expels it downwards at a high speed, which creates an upward thrust against the rocket itself, propelling it upwards.
Calculate the force required to accelerate a 5 kg object from rest to 10 m/s in 5 seconds.
easyAnswer: The acceleration a = (final velocity - initial velocity) / time = (10 m/s - 0 m/s) / 5 s = 2 m/s². Using F = ma, the force required = 5 kg × 2 m/s² = 10 N.
Describe a scenario where balanced forces are acting on an object, and explain why the object remains at rest.
easyAnswer: An example of balanced forces is a book resting on a table. The gravitational force pulling the book downwards is balanced by the normal force from the table pushing it upwards, resulting in no net force and the book remains stationary.
What role does friction play in motion according to the first law of motion?
easyAnswer: Friction is a force that opposes motion; according to the first law of motion, it is usually the external force that causes an object in motion to eventually come to a stop by opposing its motion.
NCERT Exemplar
AvailablePractice with NCERT Exemplar problems and solutions for this chapter. Exemplar problems are designed to help you master the concepts with advanced-level questions.
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