NCERT books offer a variety of questions at the end of each chapter. These can be short or long answer type questions, multiple choice type questions or fill-in-the-blanks questions. Practicing these questions of variable formats helps to enhance the problem solving skills among students. It also helps to get a thorough understanding of each topic and gain confidence to solve other related problems in the examinations.
To help students find the right approach to all the NCERT questions, jagranjosh.com presents here the detailed and accurate solutions for Class 11 Physics. These solutions will help you know the right explanation for each NCERT question and understand the technique to write perfect answers in the school examinations.
In this article we are providing NCERT Solutions for Class 11 Physics chapter 6, Work, Energy and Power. All these solutions have been prepared by the subject matter experts and will help you clear your concepts.
Students may download all the NCERT Solutions in the form of PDF.
Main topics discussed in Class 11 Physics chapter- Work, Energy and Power are:
- Introduction to the concept of work done by a body
- Notions of work and kinetic energy : The work-energy theorem
- Kinetic energy
- Work done by a variable force
- The work-energy theorem for a variable force
- The concept of potential energy
- The conservation of mechanical energy
- The potential energy of a spring
- Various forms of energy : the law of conservation of energy
Some of the questions and their solutions from NCERT Solutions for Class 11: Work, Energy and Power, are as follows:
Q. A molecule in a gas container hits a horizontal wall with speed 200 ms-1 and angle 30o with the normal, and rebounds with the same speed. Is momentum conserved in the collision ? is the collision elastic or inelastic?
Sol. Yes; Collision is elastic
The momentum of the gas molecule remains conserved whether the collision is elastic or inelastic.
The gas molecule moves with a velocity of 200 m/s and strikes the stationary wall of the container, rebounding with the same speed.
It shows that the rebound velocity of the wall remains zero. Hence,the total kinetic energy of the molecule remains conserved during the collision. The given collision is an example of an elastic collision.
Q. A trolley of mass 300 kg carrying a sandbag of 25 kg is moving uniformly with a speed of 27 km/h on a frictionless track. After a while, sand starts leaking out of a hole on the floor of the trolley at the rate of 0.05 kg s-1. What is the speed of the trolley after the entire sand bag is empty?
Sol. The sand bag is placed on a trolley that is moving with a uniform speed of 27km/h. The external force acting on the system of the sandbag and the trolley is zero. When the sand starts leaking from the bag, there will be no change in the velocity of the trolley. This is because the leaking action does not produce any external force on the system.
This is according to the Newton’s first law of motion. Hence, the speed of the trolley after the entire sand bag is empty will remain the same i.e; 27 km/h.
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