State Newton’s III law of motion. Answer: Question 21. Answer: Mention any two affects of force. Question 27. Eqn. The greater is the mass of the body; the On the other (d) A body suspended from the hook of a spring balanced in a lift which is accelerated downward, Answer: (c) A rocket explodes on midway from the ground, Question 16. The stone flies off tangentially due to inertia of direction of motion. Consider a body of mass moving with initial velocity Let a force acts on the body for time so that the velocity of the body after time is . Answer: A gun recoils backward with small speed than the bullet moving forward. Are you the Preeti I am thinking of? The CBSE Class 9 Science notes on chapter 9 ‘Force and Laws of Motion’ are available in this article. The heavy coin has more inertia than the lighter coin. Let a moving ball collides with another stationary ball lying on a ground. Which one of them will attain higher velocity ? Give reason in support of your answer. Action acts on one body and the reaction acts on another body. Momentum = mV. Answer: Newton’s Laws of Motion Questions Answer the following questions using complete sentences. Question 41. i.e. Question 60. Answer: very small time interval. A force is a physical quantity which causes or tends to cause a motion in an object at rest or changes or tends to change the direction of motion of a moving object or the shape or size of the object. Define momentum of a body. (a) Initial and final momentum remain the same as they do not depend on time. (b) 1 : 2 Answer: List two possible effects that will be caused in the motion of object. Class 9 Problem for Motion. Yes, an object moving a certain distance can have zero total displacement. Answer: Mention any two examples which can be explained on the basis of Third law of motion. Name the property of bodies to resist a change in their velocity. Inertia depends on the mass of the object. Two equal and opposite forces can cancel each other if they act on the same body. Let v1 and v2 be the velocities of body A and body B respectively after the collision. Question 9 A car start from rest and acquire a velocity of 54 km/h in 2 sec. Therefore, Newton’s second law of motion can be written in vector form as A few examples of the rotatory motion are as follows: The motion of the earth about its own axis around the sun is an example of rotary motion. Question 5. 2. 7. Why does a gun recoil backward when a bullet is fired from it ? (CBSE 2015) Answer: Question 1. be hurt due to the collision between them and the body of the car. Final momentum of the body, pf = mv From Newton’s second law of motion, Define the term force. (b) Variable A gunman gets jerk in backward direction while firing a gun. Net external force = zero. (1) gives the mathematical form of Newtons second law of motion. Question 8. Answer: Download Class 9 Science Multiple Choice Questions PDF Enhance your subject knowledge taking the help of MCQs of Class 9 Science and practice them on a regular basis. MCQs from CBSE Class 10 Science Chapter 9: Force and Laws of motion 1. Is momentum a scalar or a vector quantity ? The ball will Represent the following graphically : Question 6. its velocity increases after collision. When a number of forces acting simultaneously on a body bring about a change in its state of rest or of uniform motion in a straight line, then these forces acting on the body are said to be (CBSE 2012, 2013, 2014) Unbalanced forces. (b) a bicycle and a train? Question 35. Concise Mathematics Class 10 ICSE Solutions 2020, MCQ Questions for Class 9 Science with Answers, Social Impact Of Sex Ratio, Female Foeticide And Infanticide, Need For Reproductive Health Problems And Strategies, Maintenance Of Pregnancy And Embryonic Development, Analysis of Financial Statements Class 12 Notes Accountancy Chapter 9, Financial Statements of a Company Class 12 Notes Accountancy Chapter 8, Concise Mathematics Class 10 ICSE Solutions, (b) Cricket player lowers his hand while catching the ball. Natural tendency of an object to resist a change in its states of motion or rest If a player does not lower his hands while catching the ball, the time to stop the ball is very small. Force which opposes relative motion Give reason. Solid made of steel has the highest inertia because its mass is greater than aluminium and wooden solids. Answer: (b) Write reasons for your answer. (a) inertia of motion From this establish F = ma, where m is mass and a is acceleration. Question 29. Q2. Answer: These are helpful for the preparation of class tests and terminal exams. Question 1. (a) accelerated (a) remain same Define the first law of motion. On the other hand, the stationary ball begins to move i.e. Recoil speed of gun is inversely proportional to the mass of the gun. State the meaning of recoil velocity of a gun? Displaying Question Bank_Problem_Motion.pdf. Answer: A passenger in a moving car slips to one side of the seat when the car takes a sharp turn. (d) 5 : 12. (c) a five-rupees coin and a one-rupee coin? When the thread tied to its neck is removed, air inside the balloon rushes to the left side and the balloon moves to right side to conserve linear momentum. A passenger in a moving train tosses a coin which falls behind him. An unbalanced force is acting on an object. An object has moved through a distance. Force is a vector quantity. (ii) Find its momentum at the highest point of its flight. Will they always produce accelerations of equal magnitude ? State and verify law of conservation of momentum. Thus, force acting on the body is directly proportional to (i) its mass (m) and (ii) its acceleration (a). Total initial linear momentum of the two friends is zero as both are at rest. Answer: Justify this statement. Let u1 > u2 Let these bodies collide with each other for a small interval of time ‘dt’. Which would require a greater force — accelerating a 2 kg mass at 5 m s-2 or a 5 kg mass at 3 ms-2 ? (a) Reading shown by spring balance is 15 g wt.