The chapter Work, Power and Energy is a very important topic of Mechanics in WBJEE Examination 2018. In this article we bring to you the complete chapter notes of chapter Work, Power and Energy including topics like work, work done by a variable force, conservation of Mechanical Energy, Potential Energy of a string, power etc. These chapter notes are prepared by Subject Expert and are based on the latest syllabus of WBJEE Examination. These notes also include some previous year solved questions which will help you to understand the difficulty level of questions asked in previous year WBJEE Examinations. These notes are in very concise form and can be used for quick revision before the examination. This article will definitely help you to score full marks in this topic in WBJEE Examination 2018.
About the exam:
West Bengal Joint Entrance Examination (WBJEE) is a state level common entrance test organized by West Bengal Joint Entrance Examinations Board for admission to the Undergraduate Level Engineering and Medical Courses through a common entrance test in the State of West Bengal.
Work done for a certain spring when stretched through 1 mm is 10 Joule. The amount of work that must be done on the spring to stretch it further by 1 mm is
(a) 30 J (c) 10 J
(b) 40 J (d) 20 J
Hence, the correct option is (a).
A particle of mass m is moving in a circular path of constant radius r such that its centripetal acceleration ac, is varying with time t as ac = k2rt2 , where k is a constant. The power delivered to the particle by the forces acting on it is
(a) Zero (b) mk2r2t2
(c) mk2r2t (d) mk2rt