1. Complete Activity 10.1 (Page 113). We have discussed in the above paragraphs a number of activities which we normally consider to be work in day-to-day life. For each of these activities, ask the following questions and answer them:
(i) What is the work being done on?
(ii) What is happening to the object?
(iii) Who (what) is doing the work?
Answer:
Kamali is preparing for examinations. She spends lot of time in studies. She reads books, draws diagrams, organises her thoughts, collects question papers, attends classes, discusses problems with her friends, and performs experiments. She expends a lot of energy on these activities. In common parlance, she is ‘working hard’. All this ‘hard work’ may involve very little ‘work’ if we go by the scientific definition of work.
(i) The work is being done on Kamali herself.
(ii) Kamali is expending energy and effort in studying, reading, drawing, organizing, collecting question papers, attending classes, discussing problems, and performing experiments.
(iii) Kamali’s mental faculties and muscles are doing the work.
In the scientific sense no work is being done because there is zero force on Kamali and zero displacement.
You are working hard to push a huge rock. Let us say the rock does not move despite all the effort. You get completely exhausted.
(i) The work is being done on the rock.
(ii) The rock does not move.
(iii) You are doing the work.
In the scientific sense no work is being done because there is zero displacement of the object.
stand still for a few minutes with a heavy load on your head. You get tired. You have exerted yourself and have spent quite a bit of your energy.
(i) The work is being done on the load.
(ii) The load does not move.
(iii) You are doing the work.
In the scientific sense no work is being done because there is zero displacement of the object.
You climb up the steps of a staircase and reach the second floor of a building just to see the landscape from there. You may even climb up a tall tree.
(i) The work is being on yourself.
(ii) The object (you) is moving.
(iii) When you climb, the reaction forces according to Newton’s third law is doing the work.
In the scientific sense there is work done because there is external force and displacement of the object.
“We have discussed in the above paragraphs a number of activities which we normally consider to be work in day-to-day life. For each of these activities, ask the following questions and answer them:
(i) What is the work being done on?
(ii) What is happening to the object?
(iii) Who (what) is doing the work?” – Solved.
Related Links:
Solution to Activity 10.1
Solution to Activity 10.2
Solution to Activity 10.3
Solution to Activity 10.4
Solution to Activity 10.5
Solution to Activity 10.6
Solution to Activity 10.7
Solution to Activity 10.8
Solution to Activity 10.9
Solution to Activity 10.10
Solution to Activity 10.11
Solution to Activity 10.12
Solution to Activity 10.13
Solution to Activity 10.14
Solution to Activity 10.15
Solution to Activity 10.16
Solution to Activity 10.17
Solutions to Chapter 10 Work and Energy
