force and laws of motion class 9 questions with answers

NCERT Solutions for Class 9 Science Chapter 9: To start with, you will learn about the first, second, and third laws of motion with examples, mathematical equations, and applications. Also calculate the magnitude of the force required. When we shake the branch of a tree vigorously, leaves fall down. But when an unbalanced force is applied by the engine to change the direction of motion of the motorcar. (b) To every action there is an equal and opposite reaction, both act on different bodies. Answer: (c) there is a force 6n the ball opposing the motion. Multiple Choice Questions A driver accelerates his car first at the rate of 1.8 m/s2 and then at the rate of 1.2 m/s2. When two persons push the car, they just manage to move it at a uniform velocity. Due to the inertia of rest, the leaves tend to remain in its position and hence detaches from the tree to fall down. Answer: This is because stone is heavier than football and heavier objects offer larger inertia. When a carpet is beaten with a stick, dust comes out of it. Question 16. (b) Here initial velocity of both car and truck is same equal to v and final velocity of both is zero. Here you can get complete NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion in one place. When the bus accelerates from rest we fall backwards: When the bus’ is stationary our body is at rest but when the bus accelerates, the lower part of our body being in contact with the floor of the bus comes in motion, but the upper part of our body remains at rest due to inertia of rest. A bullet of m.ass 20 g is horizontally fired with a velocity 150 m/s from a pistol of mass 2 kg. A hockey ball of mass 200 g travelling at 10 ms-1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 ms-1. When it is beaten with a stick the carpet is set in motion, but the dust particles remain at rest. Answer: When a person jumps from a height he is in state of inertia of motion. (a) Which vehicle experiences the greater force of impact? Answer. unit of force?Answer: S.I. Answer: S.I. Answer: Answer: Question 9.What is the momentum of an object of mass m, moving with a velocity v?. Answer: (a) How can a karate expert break the slate without any injury to his hand? Tag: force and laws of motion class 9. . 14: What decides the rate of change of momentum of an object?Answer: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force. There is change in their velocities due to collision. Answer: While catching a. fast moving cricket ball, a fielder on the ground gradually pulls his hands backwards with the moving ball. Topics and Sub Topics in Class 9 Science Chapter 9 Force and Laws of Motion: These solutions are part of NCERT Solutions for Class 9 Science. The CBSE Class 9 Science notes on chapter 9 ‘Force and Laws of Motion’ are available in this article. Name two factors which determine the momentum of a body. .1 N = 1 kg m/s2. Question 4. Class 9 Science NCERT Textbook – Page 126-127 Saksham saw his karate expert friend breaking a slate. Question 13. When we stop pedaling the bicycle it stops because 2. Its S.I. Why is it advised to tie any luggage kept on the roof of a bus with a rope? Also, calculate the velocity of the combined object. Also calculate the magnitude of the force exerted by the wooden block on the bullet. This decreases the rate of change of momentum and hence the force. Question 12. Find the force acting on it if its mass is 7 tonnes (Hint : 1 tonne = 1000 kg). Important Questions for Class 12 Question 4. Explain inertia and momentum. 1: Explain Newton’s second law of motion and with the-help of an example show how it is used in sports. In this case the horse exerts a force on the ground with its feet while walking, the ground exerts an equal and opposite force on the feet of the horse, which enables the horse to move forward and the cart is pulled by the horse. … What is Motion? Question 10. 8: What is law of conservation of momentum? Ncert solutions for class 9 But when an unbalanced force is applied by the engine to change the direction of motion of the motorcar. Answer: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. (a) force (b) inertia If the collision lasts for 1 s: Name the type of forces acting on a truck. (c) Newton’s II law of motion (d) Newton’s I law of motion From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m/s. Inertia of motion: The object in the state of uniform motion will continue to remain in motion with same speed and direction unless it is acted upon by an external unbalanced force. ∴ Two bodies will move with velocity 0.26 m/s in the direction of the second body. After you have studied lesson, you must be looking for answers of its questions. Explain different types of inertia. RD Sharma solutions for class 9 Question 9. (c) both have different inertia (d) both have different momentum 7: How does a karate player breaks a slab of ice with a single blow? The luggage will resist any change in its state of rest or motion, due to inertia and this luggage has the tendency to fall sideways, forward or backward. (a) the earths gravitational force acts on it CBSE Class 9 Physics Worksheet for students has been used by teachers & students to develop logical, lingual, analytical, and problem-solving capabilities. Momentum is directly proportional to the mass and velocity of the body. Second law states/explains about the amount of force required to produce a given acceleration. While the upper part of our body stays in motion and moves forward due to inertia of motion and hence we can fall in forward direction.Hence, to avoid this we need to run forward in the direction of bus. When we are sitting in car moving in straight line, we tend to continue in our straight-line motion. The fielder catches the ball and gives swing to his hand to increase the time during which the high velocity of the moving ball decreases to zero. A truck starts from rest and rolls down a hill with a constant acceleration. . The two bodies collide and force is exerted by each body. The acceleration of the ball is decreased and therefore the impact of catching the fast moving ball4s reduced. (b) two forces act on the coin which balance each other (b) a bicycle and a train? 10: For an athletic races why do athletes have a special posture with their right foot resting on a solid supporter? Due to inertia of rest the dust particles retain their position of rest and falls down due to gravity. Inertia: The natural tendency of an object to resist a change in their state of rest or of uniform motion is called inertia. (a) both have same inertia (b) both have same momentum 1: Define force.Answer: It is a push or pull on an object that produces acceleration in the body on which it acts. Answer: Newton’s first law explains about the unbalanced force required to bring change in the position of the body. (a) a rubber ball and a stone of the same size? Topper’s Notes State the difference in balanced and unbalanced force. 1—(c), 2—(c), 3—(c), 4-(c), 5-(d), 6-(a), 7-(c), 8-(b), 9-(d), 10-(a). (a) heavier ball is dropped faster than lighter ball 10: State Newton’s III law of motion.Answer: To every action, there is an equal and opposite reaction and they act on two different bodies. Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. 4: What is balanced force?Answer: When forces acting on a body from the opposite direction do not change the state of rest or of motion of an object, such forces are called balanced forces. Answer: Athletes have to run the heats and they rest their foot on a solid supports before start so that during the start of the race the athlete pushes the support with lot of force and this support gives him equal and opposite push to start the race and get a good start to compete for the race. (b) it is not accelerated (b) What is Newton’s third law of motion? Explain, why is it difficult for a fireman to hold a hose, which ejects a large amount of water at a high velocity. A football and a stone has same mass Newton’s II law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the-force. Answer: Three examples based on Newton’s third law are : Question 17. Types of inertia:Inertia of rest: The object at rest will continue to remain at rest unless acted upon by an external unbalanced force. 9: What is momentum?Answer: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. (c) the product ‘mi/ is same for both bodies This is explained with the help of suitable examples and demonstrations. What is balanced force? RS Aggarwal Solutions for class 8 Object of mass m, is moving along a straight line with an initial velocity ‘u’, It is uniformly accelerated to velocity v in time ‘t by the application of force, Question 8. This is due to The momentum of ball A before collision is mAuA and final momentum is mAvA. Saksham’s friend showed the value of being responsible and caring friend. An automobile vehicle has a mass of 1500 kg. While the upper part of our body stays in motion and moves forward due to inertia of motion and hence we can fall in forward direction. unit is kg. An object of mass 2 kg is sliding with a constant velocity of 4 ms-1on a frictionless horizontal table. Answer: While we are travelling in a moving car, our body remains in the state of rest with respect to the seat. 18: Negative sign indicates that the direction in which the pistol would recoil is opposite to that of bullet. Question 15. (c) Newton ( (d) Newton-meter Question: What is momentum? State all 3 Newton’s law of motion. CBSE Class 9 Science extra questions for Chapter 9 - Force and Laws of Motion are prepared to cover all the key concepts involved in the chapter. Question: State Newton’s second law of motion. -ve sign of acceleration, charge in momentum and force suggests that the force is opposing the motion of motor car. Define force. What is the friction force that will be exerted on the cabinet? (b) lighter ball is dropped faster than heavier ball Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick. (b) By pulling the hand backwards it reduces the force exerted by the ball on hands. Hence, safety belt exerts a force on our body to make the forward motion slower. 11. Answer: Newton’s second law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force. A cricket ball of mass 70 g moving with a velocity of 0.5 m/s is stopped by a player in 0.5 s. What is … (ii) Unbalanced force: When two opposite forces acting on a body move a body in the direction of the greater force or change the state of rest, such forces are called as unbalanced force. It means that the object may be travelling with a non-zero velocity but the magnitude as well as direction of velocity must remain unchanged or constant throughout. Practicing these CBSE NCERT Objective MCQ Questions of Class 9 Science with Answers Pdf will guide students to do a quick revision for all the concepts present in each chapter and prepare for final exams. Thus, the acceleration of the ball is decreased and therefore the impact of catching the fast moving ball is reduced. Two bodies as shown in the figure collide with each other and join thereafter. (a) Balanced force. In the following example, try to identify the number of times the velocity of ball changes: “A football … 4: What is inertia? May 8, 2021 (updated May 8, 2021) Published by fullbag. When you kick a football it flies away but when you kick a stone you get huh why? Question 7. Choose the correct option: Define one Newton. Therefore, this sudden break may cause injury to us by impact or collision. Answer: Question 7. If no, provide a reason. An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms-1 to 8 ms-1 in 6 s. Calculate the initial and final momentum of the object. Question 13. On jumping out of a moving bus our feet touches the ground and come to rest. Momentum: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. 6. (b) A player pulls his hands backwards after holding the ball shot at high speed. It change the state of rest or of motion of an object. 1. Answer: Question 15. When he suddenly touches the ground he comes to rest in a very short time and hence the force exerted by the hard concrete surface on his body is very high, and the person gets hurt. Which of the following has more inertia: Also, find the magnitude of the force exerted on the object. (c) momentum (d) Newton Question 11.Why do you think it is necessary to fasten your seat belts while travelling in your vehicle? Answer: (d) mv. Newton’s 3rd law of motion: To every action, there is an equal and opposite reaction and they act on two different bodies. It can change the direction of motion of a body. Momentum: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. (b) Which vehicle experiences the greater change in momentum? ∴ The total momentum of the two balls remains unchanged or conserved provided no other external force acts. Question 6. Is it constant, increasing, decreasing, or zero? Chapter 2 - Is Matter Around us Pure. Explain why some of the leaves may get detached from a tree if we vigorously shake its branch. Home » Class 9 » Extra Questions » Science » Chapter 9 Force and Laws of Motion. The greater the mass of a body; the greater is its inertia. Question 3. Answer: It is due to law of inertia. 9. Explain different types of inertia. On moving/turning around the tray at faster speed the water spills because the tray and the tumbler comes into motion while the water in the tumbler remain at inertia of rest. When we kick (action) the stone it exerts an equal and opposite force (reaction) and hence it hurts the foot. RD Sharma solutions for class 7 But mass of truck is much more than that of car, hence change in momentum of truck is more than change in momentum of car. After collision, the total momentum will be= m1v1 + m2v2 (∴ v1 = v2)= (m1 + m2)v= (60 + 55)v= 115 v, ∴ According to law of conservation of momentum. Question 14. Ques 1: Define force. According to the third law of motion, the force fAB exerted by ball A on ball B and the force fBA exerted by the ball B on ball A must be equal and opposite to each other. Forces A, B,C and D are acting on the truck.Name the type of forces acting on a truck. (d) Car suffers more damage than the truck, as acceleration of car is more, its velocity falls to zero in a shorter time and consequently, its momentum changes in a shorter time. ∴ The total momentum of the two balls remains unchanged or conserved provided no other external force acts. It can change the direction of motion of a body. When we are travelling in a vehicle and sudden brakes are .applied we tend to fall forward. A bullet of mass 10 p travelling horizontally with a velocity of 150 m-1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. In CBSE Class 9 Science Chapter 9 – Force and Laws of Motion, students will study topics related to the laws of motion, inertia and mass, momentum, etc. An object of mass 1 kg traveling in a straight line with a velocity of 10 m/s collides with and sticks to … Answer: Force: It is a push or pull on an object that produces acceleration in the body on which it acts. Answer: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force. 2: What is S.I. Chapter 1 - Matter in Our Surroundings. Which of the following has more inertia: (a) a rubber ball and a stone of the same size? (a) inertia (b) momentum RD Sharma solutions for class 8 RD Sharma solutions for class 10 It will help them understand how well they have prepared, how good their time management is, and how they can improve. “A football player kicks a football to another player of his team who kicks the football towards the goal The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team”. Answer: (a) A karate player applies the blow with large velocity in a very short interval of time on the slate, therefore large force is exerted on the slate and it breaks. Answer: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. (b) a bicycle and a train? Answer: Force: It is a push or pull on an object that produces acceleration in the body on which it acts.A force can do 3 things on a body(a) It can change the speed of a body. For an athletic races why do athletes have a special posture with their right foot resting on a solid supporter? As a reaction of this force, the ground pushes the horse in a forward direction. 1: Class V students were playing cricket with the cork hall in the school campus. (c) What value of Saksham’s friend, is seen in the above case? (b) velocity is proportional to the force exerted on the ball. NCERT Textbook for Class 9 Science – Page 118 A large truck and a car, both moving with a velocity of magnitude v, have a head- on collision and both of them come to a halt after that. Answer: The forces A, B, C and D acting on the truck are: Question 1. (c) Charu showed the value of being responsible and helpful by nature. Question 5. Question 2. Question 2. Why? He tried to break the slate but Saksham’s friend stopped him from doing so and told him that it would hurt, one needs lot of practice in doing so. Important Questions for Class 10 unit is kg. 2: Saksham saw his karate expert friend breaking a slate. (b) a train (a) (mv)2           (b) mv2                    (c) 1/2 mv2                   (d) mv . Which of the following two types of forces will bring the motion in an object? With what velocity will they move after combining together? Answer: When forces acting on a body from the opposite direction do not change the state of rest or of motion of an object, such forces are called balanced forces. Question 3. NCERT Solutions for Class 9 Science Chapter 9 force and laws of motion all Intext questions given with in the chapter and end exercise given at the end of the chapters are given below. NCERT Solutions for Class 9 Science. Answer: The mass of truck is too large and hence its inertia is too high. This activity explain Newton’s III law of motion i.e., the force is exerted forward in throwing the bag full of sand and the person who is throwing it gets pushed backward. (a) kgm/s (b) kgm/s2 (b) Frictional force exerted on the body is more than 50 N Answer: The natural tendency of an object to resist a change in their state of rest or of uniform motion is called inertia. This solution contains questions, answers, images, step by step explanations of the complete Chapter 9 titled Force and Laws of Motion of Science taught in class 9. What is inertia? Answer: A force of one Newton produces an acceleration of 1 m/s2 on an object of mass 1 kg. The rate of change of momentum of an object is proportional to Answer: Momentum of two bodies before collision is equal to the momentum after collision. What is inertia? Here we have given Class 9 NCERT Science Text book Solutions for Chapter 9 Force and Laws of Motion. State the meaning of recoil velocity of a gun? Its S.I. Question 5. (c) Which vehicle experiences the greater acceleration? A force of 50 N moves a body. Question 15. How does a karate player breaks a slab of ice with a single blow? RS Aggarwal Solutions for class 9 Forces acting on a body from the opposite directions are same. unit is kgm/s. Answer: Question 17. Solution 1. … The S.I. Answer: Question 6. 4: Explain why it is dangerous to jump out of a moving bus. Therefore, this sudden break may cause injury to us by impact or collision. Answer: While we are travelling in a moving car, our body remains in the state of rest with respect to the seat. Answer: An object remains in a state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force. Answer: Question 2. Answer: A vehicle moving on mountains is in the inertia of motion. Why do fielders pull their hand gradually with the moving ball while holding a catch? (b) … Answer: Momentum of two bodies before collision is equal to the momentum after collision.In an isolated system, the total momentum remain conserved. Types of forces: Question 4. (a) Why it was safe to play with soft ball and not with hard cork ball? (Assume that all persons push the motorcar with the same muscular effort.) Question 9. Answer: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force. Answer: The forces A, B, C and D acting on the truck are:A → driving forceB → reacting forceC → frictional forceD → weight/gravitational force. Question 3. 8: State Newton’s second law of motion.Answer: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force. Answer: While moving in a bus our body is in motion. At a sudden turn there is a tendency of vehicle to fall off the road due to sudden change in the line of motion hence the roads are inclined inwards so that the vehicle does not fall down the mountain. (c) act in same direction (d) both (a) and (c) CBSE Sample Papers for Class 10, RS Aggarwal Solutions for class 12 State Newton’s second law of motion. Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India. Three examples of inertia in daily life are:1. Explain how momentum gets conserved in collision of two bodies. In an isolated system, the total momentum remain conserved. Types of inertia: Explain. What is the relation between Newton’s three laws of motion? Answer: Let each person applies a force F on a motorcar of mass, m = 1200 kg. Answer: And Newton’s third law explains how these forces acting on a body are interrelated. (a) It can change the speed of a body. C and D are acting on the truck. We slip to one side of the seat due to the inertia of our body. Give 3 examples in daily life which shows inertia. Answer: Question 14. 12: Name the factor on which the inertia of the body depends.Answer: Inertia of a body depends upon the mass of the body. The mass of an object is a measure of its inertia. Answer: According to second law, F = ma If F = 0, a =0 since m ≠ 0, But a = \(\frac{v-u}{t}\) or, v – u =0 so, v = u for whatever time t is taken. Ncert solutions for class 11 Action and reaction forces Why are roads on mountains inclined inwards at turns? These questions … Explain Newton’s second law of motion and with the help of an example show how it is used in sports. Answer: Newton’s second law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force. All NCERT textbook questions have been solved by our expert teachers. (a) the batsman did not hit the ball hard enough. But when driver applies sudden breaks or stops the car our body tends to continue in the same state of motion because of its inertia. The fielder catches the ball and gives swing to his hand to increase the time during which the high velocity of the moving ball decreases to zero. An object of mass 2 kg is sliding with a constant velocity of 4 m/s on a friction less horizontal table. (d) there is no unbalanced force on the ball, so the ball would want to come to rest. What is frictional force? Answer: Question 8. (a) What conclusion can you draw about the acceleration? Calculate the initial recoil velocity of the rifle. 9. Comment on these suggestions. What are different types forces? Question 1. The ball slows to a stop because Hence we fall in backward direction. Explain. Answer: A karate player applied the blow with large velocity in a very short interval of time on the ice slab which therefore exerts large amount of force on it and suddenly breaks the ice slab. Question 3. What Is Motion – Definition, Types, Examples. Calculate the total momentum just before the impact and just after the before the impact and just after the impact. You can opt for Chapter 9 - Force and Laws of Motion NCERT Solutions for Class 9 Science PDF for Upcoming Exams and also You can Find the Solutions of All the Maths Chapters below. If the object was initially in a state of motion, then in accordance with the first law of motion, the object will continue to move in same direction with same speed. 6: What is inertia?Answer: The natural tendency of an object to resist a change in their state of rest or of uniform motion is called inertia. Karnataka Board Class 9 Science Chapter 9 Force and Laws of Motion KSEEB Solutions Class 9 Science Chapter 9 Intext Questions. A batsman hits a cricket ball which then rolls on a level ground. The same motorcar can be pushed by three persons to produce an acceleration of 0.2 ms-2. Question 1. (p = mv). If yes, state the conditions that must be placed on the magnitude and direction of the velocity. Give its unit and define it. 1N = 1kg m/s2 RD Sharma solutions for class 6. Answer: Two factors on which momentum of a body depend is mass and velocity. The first section of the chapter deals with balanced and unbalanced forces.

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