Overview of the chapter
To study this chapter efficiently first you have to understand all the definitions and terminologies, given the chapters and try to interpret them in a very logical way. You must be good at basic laws like the law of energy conservation and theorems like a work-energy theorem Because you might get conceptual questions based on these laws And theorems. You will get various real-life application based problems on the concept like a work-energy theorem, law of energy conservation, Collision, Power.
For example, let's have a look question which is based on real-life activities and was asked in jee main 2016 from this chapter.
Q- A person who is trying to lose weight by burning his fats lifts a mass of 10 kg 1000 times up to a height of 1 m. And also assume that the potential energy lost each time he lowers the mass is dissipated. By considering the work done only when the weight is lifted up then tell How much fat will he use up? ( If Fat supplies 3.8× J of energy on burning 1 kg fat which is converted to mechanical energy with a 20% efficiency rate. )
To solve these questions you first find work done by the person in lifting the weight
Which is equal to W=mgh
Which is equal to E
Then find Total fat burn by dividing W by E
Which is equal to
First, you should have good command over the concepts of Work Power and Energy and you should also know how to apply them well at the time of the entrance exam or while solving questions. Entrance 360 will help you to understand each concept from this chapter since it provides you theory, questions with solutions and video lectures on each important concepts. For each concept practice enough problems so that you are through with the concept. Take mock test and practice previous year questions. Through practice, you will come to know how to approach a question. There are direct formulas that can be applied to certain questions.
To Solve Work Power Energy Problems
For Work Power and Energy chapter concepts in NCERT is enough and practice questions which are asked in previous questions and you can follow other standard books available for JEE preparation like Concepts of Physics (H. C. Verma) and Understanding Physics by D. C. Pandey (Arihant Publications). You don't have to study the whole book to understand the concept from this chapter because Entrance 360 will provide you exact page number and line number of these books where you will get these concepts to read.
A 60 HP electric motor lifts an elevator having a maximum total load capacity of 2000 kg. If the frictional force on the elevator is 4000N , then the speed of the elevator at full load is close to: (1 HP=746 W, g=10 ms-2).
A particle (m=1 kg) slides down a frictionless block(AOC) starting from rest at a point A (height 2 m). After reaching C, the particle continues to move freely in air as a projectile. When it reaches its highest point P (height 1 m), the kinetic energy of the particle (in J) is (take g=10 ms-2):-
A body A, of mass has an initial velocity of . It collides elastically with another body, B of the same mass which has an initial velocity of . After collision, A moves with a velocity The energy of B after collision is written as . The value of x is __________.