Class 9 Science
Work and Energy
Question 1.
Define work done.
Question 2.
Does work have direction? What is its unit?
Question 3.
What do you understand by 1 joule of work done?
Question 4.
A force of 7 N is acting on an object. The object is displaced through 3 m in the direction of the force. What is the work done in this case?
Question 5.
A porter lifts a luggage of 20 kg from the ground and puts it on his head 2.0 m above the ground. Calculate the work done by him on the luggage.
Question 6.
A pair of bullocks exerts a force of 150 N on a plough. The field being ploughed is 10 m long. How much work is done in ploughing the length of the field?
Question 7.
How do you define the term ‘energy’?
Question 8.
What should be the unit for energy?
Question 9.
What can be the various forms of energy?
Question 10.
How do you define the kinetic energy of an object?
Question 11.
Derive a formula for kinetic energy of an object having mass m and moving with uniform velocity v.
Question 12.
An object of mass 20 kg is moving with a uniform velocity of 5 m-s–1. What is the kinetic energy possessed by the object?
Question 13.
What is the work to be done to increase the velocity of a car from 45 km-h–1 to 75 km-h–1 if the mass of the car is 3000 kg?
Question 14.
How do you define the potential energy possessed by an object?
Question 15.
Give an expression for gravitational potential energy of an object at a height, h.
Question 16.
Find the energy possessed by an object of mass 20 kg, when it is at a height of 5 m above the ground. Given, g = 9.8 m-s–2.
Question 17.
An object of mass 10 kg is at a certain height above the ground. If the potential energy of the object is 500 J, find the height at which the object is with respect to the ground. Given, g = 10 m-s–2.
Question 18.
What is the total mechanical energy of an object?
Question 19.
How do you define ‘Power’?
Question 20.
An electric bulb of 75 W is used for 5 h per day. Calculate the ‘units’ of energy consumed in one day by the bulb.
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In summary, problem-solving after learning a theoretical concept on CBSE Work and Energy Class 9 Science is an essential part of the learning process. It enhances your understanding, critical thinking abilities, and retention of knowledge. Moreover, it equips you with valuable skills that are applicable in academic, personal, and professional contexts.
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Practicing questions plays a pivotal role in achieving excellence in exams. Just as the adage goes, "Practice makes perfect," dedicating time to solve a diverse range of exam-related questions yields manifold benefits. Firstly, practicing questions allows students to familiarize themselves with the exam format and types of problems they might encounter. This familiarity instills confidence, reducing anxiety and improving performance on the actual exam day. Secondly, continuous practice sharpens problem-solving skills and enhances critical thinking, enabling students to approach complex problems with clarity and efficiency. Thirdly, it aids in identifying weak areas, allowing students to focus their efforts on improving specific topics. Moreover, practice aids in memory retention, as active engagement with the material reinforces learning. Regular practice also hones time management skills, ensuring that students can allocate appropriate time to each question during the exam. Overall, practicing questions not only boosts exam performance but also instills a deeper understanding of the subject matter, fostering a holistic and effective learning experience.
All About Daily Practice Problems on Class 9 Science Work and Energy NCERT Chapter 11
Our Daily Practice Problems (DPPs) offer a diverse range of question types, including Multiple Choice Questions (MCQs) as well as short and long answer types. These questions are categorized into Easy, Moderate, and Difficult levels, allowing students to gradually progress and challenge themselves accordingly. Additionally, comprehensive solutions are provided for each question, available for download in PDF format - Download pdf solutions as well as Download pdf Questions. This approach fosters a holistic learning experience, catering to different learning styles, promoting self-assessment, and improving problem-solving skills. With our well-structured DPPs, students can excel in exams while gaining a deeper understanding of the subject matter. Hope you found the content on Class 9 Science Work and Energy NCERT Chapter 11 useful.
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