In the following activity the values of a and b can be changed, That is by changing a:b we can create many examples. Teachers should give lot of practice to the students and encourage them to construct their own examples.

In the following activity, the values of a and b can be changed. That is by changing a:b , we can create many example. (NAV_MAT_IX_P01_C04_E03_001_Q01.png" width="80%">

Answer the following questions: What are the different ways in which the velocity of a body can be changed? Give one examples in each case.

Students should take examples of their own and practice construction of triangles.

Read the following paragraph and answer the questions: If heat is exchanged between a hot and cold object, the temperature of the cold object goes on increasing due to gain of energy and the temperature of the hot object goes on decreasing gue to loss of energy. The change in temperature continues till the temperatures of both the objects attain the same value. In this process, the cold object gains heat energy and the hot object loses haet energy. If the system of both the objects is isolated from the environment by keeping it inside a heat resistance box (meaning that the energy exchange takes place between the two objects only ), then no energy can flow from inside the box or come into the box. Which principle do we learn about from this process?

A student performed following two activities in school laboratory: Activity 1: Addition of zinc dust into copper sulphate solution taken in a test tube. Activity 2: Addition of an iron nail into copper sulphate solution taken in a test tube. He noted down his observations and concluded that chemical reaction occurs in both the cases based on the observed colour change of the resulting solution. Based on these activities, what can you conclude about the reactivity of elements zinc and iron as compared to that of copper?

In which of the following examples can you sense motion? A. The flight of a bird B. A stationary train C. Leaves flying through air D. A stone lying on a hill

In the following examples , can the segment joining the given points from a triangle ? If triangle is formed , state the type of the triangle considering sides of the triangle. (iii) A (sqrt(2) ,sqrt(2)) , B (-sqrt(2) ,-sqrt(2) ), C (-sqrt(6) ,sqrt(6) )

Paragraph-based questions Read the paragraph and answer the questions given below: Disasters can be properly classified into three categories. viz. natural disasters, technological disasters and man-made disasters. The forces that cause natural disasters cannot be controlled. Moreover, they are becoming more frequent in the current years due to phenomena of climate change. On and off incidences of cyclones, cloud bursting, floods, etc. are creating havoc in the lives of people. Technological disasters are due to improper and callous behavior at the different processes carried out in technical establishments. Man-made disasters are conflicts arising due to different religions, regions and terrorism. Give any one example of technological disaster that shook the entire India.

In the following examples,can the segment joining the given points form a triangle?If triangle is formed,state the type of the triangle considering sides of the triangle.(iii)A(sqrt 2,sqrt 2),B(-sqrt 2,-sqrt 2),C(-sqrt 6,sqrt 6).

Solve the following examples: (numerical problems) A particle of mass 10^(-10) kg moves in a straight line. Figure shows how its speed changes with time. Answer the following questions based on it. Find the average force acting on the particle in the time interval B'C'.