It was summer season and Ishant was sleeping at top of roof when heard some noise at downstairs when he looked down, he saw that two robbers were holding his brother at gun point , suddenly he saw a big drum near to him and he rolled the drum from the stairs which hit one of the robber who was holding gun and robber fell down. In mean time other one run away and the family caught that robber and handed him over to the police.
What is meant by rolling without slipping?

Ravinder and Mohender were discussing the role of Physics in society. Ravinder said to Mahender that Physics does not have any impact on society. He had no knowledge of science as he was the student of Arts stream. Ravinder who is the science student of class XII explained him that the fate of society is intimately linked with Physics because whatever is discovered in Physics, it immediately effects the society. The advancement in the field of communication such as radios, computers, TVs and mobile phones connect the people with each other. Nuclear energy have brought a profound change in the thinking and living style of the human beings.
(i) What values are displayed here by Ravinder?
(ii) Give any five discoveries which has effected the society more.

Shansher, a student of class X asked his physics teacher, "Why the refrigerator does not cool the room if it is kept open? Whereas the refrigerator cooles the eatables put in it. His teacher answered him that the refrigerator does not cool the room in which it is kept. When a refrigerator is working in a closed room with its door closed, it is rejecting heat from inside to the air in the room. So temperature increases gradually. When the door of the refrigerator is kept open, heat rejected by the refrigerator to the room will be more than the heat taken by the refrigerator from the room. Therefore the temperature of the room will increase at a slower rate compared to the first case.Shansher thanked his teacher for explaining it very well.
(i) What values are shown by 5hansher?
(ii) Calculate the efficiency of Carnot's engine working between steam point and ice point.

We know that all the bodies fall downwards with an accelerating velocity due to the acceleration due to gravity 9.8 m/s² but rain drops do not fall to earth as the other bodies do. Sohan was a student of science. His father asked Sohan the reason of drops not falling to the earth with the velocity equal to other bodies. He explained this reason that all bodies fall freely irrespective of their mass and size but in case of rain drops, there is a retarding force of viscosity due to the air medium. After falling through some distance, the drops attains a constant velocity which is known as terminal velocity. Sohan's father was satisfied with his son's answer.
(i) What values are displayed by Sohan?
(ii) What do you mean by viscosity and terminal velocity?

Suresh went to London to his elder brother Lalit who is a Civil Engineer there. Suresh found there the currency is quite different from his country. He could not understand pound and how it is converted into rupees. He asked there an Englishman how far is the Central London from here. He replied that it is 16 miles. Suresh again got confused because he never used these units in India. In the evening Suresh inquired all about it. His brother told him about the unit system used in England. He explained his brother that here F.P.S. system is used. It means, distance is measured in foot, mass in pound and time in seconds whereas in India it is MKS system.
(i) What values are displayed by Suresh?
(ii) How many unit systems are there?