4. This change is also brought on by the goalkeeper of team B, who applies the force to kick the ball forward. A motorcar is moving with a velocity of 108 km/h and it takes 4 second to stop after the brakes are applied. NCERT Class 9 Science Chapter 9 Force and laws of motion, also describes the natural tendency of objects to resist a change in their state of rest or of uniform motion known as inertia in a detailed way. NCERT Solutions offer comprehensive answers to all the questions to help students in their preparations. What is the relation between Newton’s three laws of motion? Therefore, this sudden break may cause injury to us by impact or collision. (b) What is Newton’s third law of motion? NCERT for Class 9 Science Solutions is made available in both PDF and web format for ease of access. Answer: Force: It is a push or pull on an object that produces acceleration in the body on which it acts. Question 10. 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. Define force. Answer: The third law of motion states that action is always equal to the reaction but they act on two different bodies. Explain why some of the leaves may get detached from a tree if we vigorously shake its branch. The object will keep moving with a non-zero velocity. Question 4. The ball slows to a stop because (a) the batsman did not hit the ball hard enough. It is a detailed and well-structured concept-based learning solution aimed at imparting confidence to face the board and competitive exam. 5. Name the factor on which the inertia of the body depends. Now, a force in the forward direction is applied to the passengers because their inertia resists the change in the motion of the bus. Here on AglaSem Schools, you can access to NCERT Book Solutions in free pdf for Science for Class 9 so that you can refer them as and when required. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Download 9th Science chapter 9 Intext questions given on Page 118, … Since the mass of the car is very high, the force exerted on the insect during the collision is also very high. Calculate the total momentum just before the impact and just after the impact. 5. Answer: Question 7. Answer: Question 4. Therefore, the recoil velocity of the rifle is 0.4375 meters per second in the direction opposite to the trajectory of the bullet (backward direction). The velocity at which the horse can move by applying a force on the earth depends on the mass of the horse (and the cart attached to it). Question 4. Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India. If the collision lasts for 1 s: Question 8. And Newton’s third law explains how these forces acting on a body are interrelated. State all 3 Newton’s law of motion. (c) a five-rupee coin and a one-rupee coin? 3. Define force. However, Rahul’s suggestion that the change in the momentum is the same contradicts the law of conservation of momentum. (adsbygoogle = window.adsbygoogle || []).push({}); Question 1: A girl of mass 40 kg jumps with a horizontal velocity of 5 m/s onto a stationery cart with friction-less wheels. The acceleration of the train is 1.94 m.s-2. 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. This opposite force is the fictional force exerted on the cabinet. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 ms-2? Answer: Inertia of a body depends upon the mass of the body. In an isolated system, the total momentum remain conserved. What are different types forces? Question 10.Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity.