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.
(i) What values of Ishant saved his brother's life?
(ii) What kind of motion is described by the drum?
(iii) If a thin hollow cylinder, opened at both the ends and weighing 5 kg rolls with a speed of 10 m/s without slipping. What is the kinetic energy of cylinder?
(iv) What is meant by rolling without slipping?

Deepa's uncle was surprised to see the fast changes in the world. He is not so educated. He asked Deepa to tell him the names and qualities of some persons who have contributed for bringing the rapid changes in the world. Deepa who is science graduate explained about some discoveries and the names of scientist who have done a marvellous work in physics.
(i) Why Deepa's uncle was so curious to know things changed recently?
(ii) What values are displayed by Deepa?
(iii) Name at least three Indian scientists.

Tajender was going to Agra with his father in the month of June. It was too hot to tolerate that day. His father was driving the car. He stopped on a petrol pump in the way and got filled the tank of the petrol in the car. He also checked the air in the tyres of the car at air pump. He asked the worker who was there to fill the air that fill the air in the tyre lesser than the normal air. Tajender immediately asked the reason behind it. His father explained that while driving, the air in the tyres expand due to the heat produced by the friction between the road and tyres. Tajender got the answer and became happy.
(i) What values Tajender exhibit?
(ii) Can you design a heat Engine of 100% efficiency? Explain your answer.

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?

Rajeshwer and his friends went to a hill forest for a plant collection tour. One of the friends Rajender Rana went to a different direction and entered a dense forest. He was searching a very useful and promodeal plant. When he searched that plant, he loudly called his friend Rajeshwer. After afew seconds he heard the same sound as he just spoken. He afraid assuming that there was a ghost in nearby forest. He started erving. Somehow Rajeshwar heard his sound and found him. Again Rajender Ram made a loud sound, this sound was again copied by somebody. Rajender repeated that same ghost is there. Rajeshuiar convinced him that it is nothing but it is reflection of sound. Now Rajender Rana became normal.
(i) What values/qualities were displayed by Rajeshwar?
(ii) What is echo?
(iii) If a reflector is situated at a distance of 860 m from a sound source, what is the time of echo?
Speed of sound in air at a room temperature can be taken as 344 m/s.