Mechanical energy is conserved (neither gained nor lost) only when conservative forces do work upon objects. When the force and the displacement act in the same direction, positive work is done. Powered by, CBSE MASTER | NCERT Textbooks Exercises Solutions, NCERT Class VI (6th) Social Science -Geography, NCERT Class VI History - Social Studies (Our Pasts-I), NCERT Class VI Social Science - Social and Political Life-1, CBSE Class VIII (8th) Science | All Chapters Solved Exercises, CBSE Class VI ( 6th) Mathematics Chapter 1 : Knowing our Numbers -Try These (Extra Solved Questions and Examples with in Chapter), CBSE Class IX ( 9th) Science | Chapter 8. Physical Features Of India | Geography | CBSE Class 9th Question 1. Mensuration CBSE Class VI (6th) Mathem... Chapter 10. Work done by F; WF=F. d. FALSE (sort of) - Kinetic energy depends upon mass and speed. n. TRUE - A force which acts in a direction opposite the motion of an object will do negative work. g. TRUE - This is the conservation of energy principle and one that you need to firmly understand. d. The force of friction acts upon a baseball player as he slides into third base. If the friction constant between surface and box is 0,3; find the work done by F, work done by friction force and work done by resultant force. A conservative force must be doing work in order for there to be a transformation of energy. FALSE - If a force does not add mechanical energy to a system of objects, then it is likely a conservative force (provided it doesn't remove mechanical energy either). f. The force is backwards and the displacement is forwards. Fibre to Fabric Chapter 4. The sort of indicates that a force is also considered a conservative force if it does work and does not add mechanical energy to an object. (A) 6:1 Motion | Lesson Exercises, CBSE Class 7th (VII) English Chapter 2. Work and Energy - Science (Physics) | Multiple Choice Questions (MCQs) | CBSE Class 9th Question 11. h. This is a straightforward question; no tricks here. i. A. A 1-kg object falls from a height of 10 m to a height of 6 m. The final potential energy of the object is approximately 40 J. Why did the king want to know answer to three questions? FALSE - The final potential energy is calculated as PE = m•g•h = (1 kg)•(~10 m/s/s)•(6 m) = ~60 J; the loss in potential energy during this 4-m fall is -40 J. k. FALSE - The object will either gain or lose mechanical energy, but not necessarily potential energy. An object has mov... Comprehension Check (Page,22) Page No.17 Question 1. f. TRUE - As objects free-fall, the height (h) decreases; subsequently, the PE decreases. Question 1. (D) 77%, 2. When the force and the displacement act in the opposite direction, negative work is done. (C) 44% (B) 100 If a non-conservative force acts upon an object, then the object will either gain or lose mechanical energy. J, Object C: KE = 0.5•(1.0 kg)•(5.0 m/s)2 = ~13 J (12.5 J), Object D: KE = 0.5•(5.0 kg)•(2.0 m/s)2 = 10. Consider a car moving at constant speed along a level surface. Using the approximation that g = ~10 m/s/s gives much quicker results. Answer: See questions above; explanations given below. Chapter 1. m. As the child swings, she traces out a circular arc and as such the tension (centripetal) is perpendicular to the direction of motion (tangent). (C) 8:1 And even if v is negative, v2 will always be positive. j. e. TRUE - The equation states that PEgrav = m•g•h; if the h is doubled, then the PE will be doubled as well. c. The force is vertical and the displacement if horizontal; they make a 90 degree angle. g. FALSE - A N•m is a Joule and that is a unit of work (not power). When the force and the displacement act in the opposite direction, negative work is done. TRUE (sort of) - This statement is true (sort of); when only conservative forces are doing work, an object has its kinetic energy transformed into potential energy (or vice versa) without the total amount of the two being altered. e. A busy spider hangs motionless from a silk thread, supported by the tension in the thread. Nutrition in Plants Chapter 2. FALSE - Potential energy has nothing to do with speed; an object could be moving at an elevated position. c. The force is backwards and the displacement is forwards. What is the initial velocity? Home » NEET Physics Objective Questions » 300+ TOP MCQs on Work, Energy and Power and Answers NEET Physics is the very imporatant paper in the Medical Entrance EXAM. Why is diffusion insufficient to meet the oxygen requirements of multicellular organisms like humans? Include all that apply. Consider a particle of mass m which is driven by a machine that has a constant power k Watts. e. TRUE - Watt is the unit of power? (A) 440J Practice daily with these NEET Physics objective questions on air pollution knowledge & problem-solving skills along with time management. TRUE - Since force and speed are given, use Power = F•v. Calculate the final kinetic energy of a block of mass if the mass of the block is 10kg and has a constant velocity of 10m/s. Asked by Mail.nehasharmaa 19th February 2019 10:13 AM Therefore, kinetic energy can never be a negative value. If you missed it, reread the question, paying careful attention to the "with the vertical" part. 2) View Solution. H. A force is applied by a chain to a roller coaster car to carry it up the hill of the first drop of the Shockwave ride.