6. Answer the following questions in one sentence. [Refer to Session 11.3 ] (i) What is a satellite? (ii) Name some uses of artiﬁcial satellites. (iii) What is the full form of NASA? 49 CHAPTER 11. STARS AND THE SOLAR SYSTEM

(iv) Which was the ﬁrst artiﬁcial Indian satellite? (v) Name a few artiﬁcial satellites launched by India. 7. Fill in the blanks. [Refer to Session 11.3 ] (i) Sun is a star located in the galaxy called . (ii) Asteroids can only be seen using a . (iii) Man made satellites are known . as (iv) Halley’s comet appears after every . (v) A deﬁnite path in which a planet revolves around the Sun is called an . (vi) is called the morning and evening star. (vii) Mercury, Venus, Earth and Mars are called . CHAPTER 11. STARS AND THE SOLAR SYSTEM 50

Short Answer Type Questions 8. Answer the following questions in 3-4 sentences. (i) [(Session 11.2)] Write about partial and total solar eclipse. (ii) [(Session 11.2)] Write about annular and hybrid eclipses. 9. Answer the following questions in 3-4 sentences. 51 (i) [(Session 11.3)] What forms our solar system? CHAPTER 11. STARS AND THE SOLAR SYSTEM

(ii) [(Session 11.3)] What is a constellation? Long Answer Type Questions 10. Answer the following questions in 6-8 sentences. (i) [(Session 11.1)] Write a note on a sundial. CHAPTER 11. STARS AND THE SOLAR SYSTEM 52

11. Answer the following questions in 6-8 sentences. (i) [(Session 11.2)] Write about the types of lunar eclipses. 12. Answer the following questions in 6-8 sentences. (i) [(Session 11.3)] Give an account on the planets of our solar system. CHAPTER 11. STARS AND THE SOLAR SYSTEM 53

AS2-Asking questions and making hypothesis Long Answer Type Questions 13. Answer the following questions in 6-8 sentences. (i) [(Session 11.2)] You have been observing the shape of the moon for a period of one month. What is the hypothesis you would make for the changing shapes of the moon? Give reasons. CHAPTER 11. STARS AND THE SOLAR SYSTEM 54

AS3-Experimentation and ﬁeld investigation Short Answer Type Questions 14. Answer the following questions in 3-4 sentences. (i) [(Session 11.1)] Write a brief procedure of an activity which can be conducted to prove that the length of a shadow changes from morning till evening. (ii) [(Session 11.1)] Write an activity which can be performed to understand the North–South movement of the Sun. CHAPTER 11. STARS AND THE SOLAR SYSTEM 55

AS4-Information skills and projects Long Answer Type Questions 15. Answer the following questions in 6-8 sentences. (i) [(Session 11.1)] Collect information about the distance of each planet from Earth. Name the planets which are closest to Earth and farthest from Earth. CHAPTER 11. STARS AND THE SOLAR SYSTEM 56

16. Answer the following questions in 6-8 sentences. (i) [(Session 11.3)] Following table shows some information about all the planets in the solar system: Planet Distance From the Volume (Earth =1) Surface Gravity Number of Mercury Sun (Astronomical 0.56 (Earth =1) moons(Known in Venus units) 0.87 0.38 2012) Earth 0.4 1 0.9 0 Mars 0.7 0.15 1 0 Jupiter 1 1,300 0.38 1 Saturn 1.5 760 2.36 2 Uranus 5.2 63 1.06 67 Neptune 9.5 58 0.89 62 19 1.1 27 30 13 Based on the information from the table answer the following questions: a) Which planet is closest to the Sun? b) Which planets have no moons? c) Is Mars bigger or smaller than Earth? d) Which planet is closest in size to Earth? e) Which planet is farthest from Sun? CHAPTER 11. STARS AND THE SOLAR SYSTEM 57

AS5-Communication through drawing and model making Long Answer Type Questions 17. Answer the following question. (i) [(Session 11.1)] Draw a diagram of the solar system. CHAPTER 11. STARS AND THE SOLAR SYSTEM 58

18. Answer the following question. (i) [(Session 11.2)] Draw the different phases of the moon. CHAPTER 11. STARS AND THE SOLAR SYSTEM 59

19. Answer the following question. (i) [(Session 11.3)] Observe the sky at night. Identify and draw the diagram of constella- tions. CHAPTER 11. STARS AND THE SOLAR SYSTEM 60

AS6-Appreciation and aesthetic sense, Values Long Answer Type Questions 20. Answer the following questions in 6-8 sentences. (i) [(Session 11.3)] How do you appreciate the beauty of the organized arrangement of the universe? CHAPTER 11. STARS AND THE SOLAR SYSTEM 61

AS7-Application to daily life, concern to bio diversity Long Answer Type Questions 21. Answer the following questions in 6-8 sentences. (i) [(Session 11.3)] The ﬁrst artiﬁcial satellite launched by India was Aryabhatta. Mention some applications of artiﬁcial satellites which have been useful for human beings. CHAPTER 11. STARS AND THE SOLAR SYSTEM 62

Objective Questions AS1-Conceptual Understanding 22. Choose the correct answer. (i) A very rare form of solar eclipse that changes from an annular to a total solar eclipse along the path: (A) Partial solar eclipse (B) Hybrid eclipse (C)Total solar eclipse (D)Annular eclipse (ii) The different patterns formed by different group of stars in the night sky are called (A) star patterns (B) pole star (C)cellestial objects (D) constellations (iii) Pournami is (B) half moon night (A) full moon day (C)old moon light (D)new moon light (iv) Any celestial body revolving around another celestial body is called its (A) axis (B) moon (C)heavenly body (D) satellite (v) The deﬁnite path in which a planet revolves around the sun is called its (A) milky way (B) galaxy (C) rotation (D) orbit (vi) A lunar eclipse occurs when CHAPTER 11. STARS AND THE SOLAR SYSTEM 63

(A) shadow of the earth falls on the moon (B) shadow of the moon falls on the earth (C)shadow of the sun falls on the earth (D)shadow of the earth falls on the sun (vii) How many days does it take for planet Venus to complete one revolution around the Sun? (A) 365 days (B) 88 days (C)687 days (D)225 days AS4-Information skills and projects 23. Choose the correct answer. (i) The planet which is known as the morning or an evening star is (A) Mars (B) Mercury (C) Venus (D) Moon (ii) The ﬁrst artiﬁcial satellite built and launched by India is (A) INSAT (B) Aryabhatta (C) IRS (D) EDUSAT (iii) During a clear night sky, bright light streaks are often visible. These are commonly known as shooting stars. The actual name for these light streaks is (A) comet (B) meteors (C) asteroids (D)falling stars AS5-Communication through drawing and model making 24. Choose the correct answer. (i) Which of the following ﬁgures depicts the position of pole star correctly? CHAPTER 11. STARS AND THE SOLAR SYSTEM 64

(A) (B) (C) (D) CHAPTER 11. STARS AND THE SOLAR SYSTEM 65

12. GRAPHS OF MOTION SESSION 1 INTRODUCTION TO GRAPHS OF MOTION 1.1 Mind Map 1.2 Terminology i. Motion – A body is said to be in motion if it changes its position with respect to its surroundings. ii. Distance – The actual length of the path covered by a body is called the distance travelled by the body. SESSION 1. INTRODUCTION TO GRAPHS OF MOTION 66

iii. Average speed – The distance travelled by an object in a unit of time is called the average speed of the object. iv. Distance –time graph – A graph plotted for distance versus time is called distance–time graph. v. Uniform motion – If an object covers an equal distance in equal time intervals it is said to be in uniform motion. vi. Map – A map is a diagrammatic representation of an area of land or sea showing physical features, cities, roads, etc. vii. Graph – A graph is a diagram showing the relation between variable quantities, typically of two variables, each measured along one of a pair of axes at right angles. 1.3 Solved Examples Q1. Can we guess the unit of speed if the distance covered is measured in centimeters and the time in seconds? (Refer to TB page 171) A. If the distance is taken in centimeters and time is taken in seconds, the unit of speed will be centimeter per second. But the SI unit of speed is meter per second. So the distance in centimeters should be converted to meters to make the unit of speed meter per second. Q2. What will the unit of speed be if the distance covered is measured in meters and the time in minutes? (Refer to TB page 171) A. If the distance is taken in meters and time is taken in minutes, the unit of speed will be meter per minute. But the SI unit of speed is meter per second. So the time in minutes should be converted to seconds to make the unit of speed meter per second. Q3. Raja travelled 15 kilometers in 3 hours. Calculate his average speed and write the correct unit of speed. (Refer to TB page 171) A. Average speed = Total Total distance travelled time taken to cover the distance = 15 km = 5 km/h 3 h SESSION 1. INTRODUCTION TO GRAPHS OF MOTION 67

1.4 Key Concepts i. Average speed = Total Total distance travelled time taken to cover the distance ii. When the distance is measured in kilometers and the time in hours, the unit of speed will be kilometer per hour or kmph or km/h. iii. When the distance is measured in meter and the time in seconds, the unit of speed will be meter per second or m/s. iv. Different types of motion can be represented by distance–time graphs. v. In a distance–time graph, time is plotted on the X–axis and distance covered is plotted on the Y–axis. vi. The speed of an object travelling with uniform motion does not change. In such cases the speed and the average speed are the same. SESSION 1. INTRODUCTION TO GRAPHS OF MOTION 68

SESSION 2 GRAPHS OF OBJECTS MOVING AT DIFFERENT UNIFORM SPEEDS 2.1 Mind Map 2.2 Terminology i. Slope– Slope refers to the steepness of a line or surface. ii. Speed – The distance covered by an object in unit time is called speed. SESSION 2. GRAPHS OF OBJECTS MOVING AT DIFFERENT UNIFORM S... 69

2.3 Key Concepts i. Distance–time graph of uniform motion is a straight line. ii. Greater the angle, greater is the slope for a graph line. iii. Two graphs can be compared visually only if they have the same scale. iv. The faster the speed of uniform motion the greater will be the slope of the graph line. v. Slope of the distance–time graph line shows the speed of the object at that time. 2.4 Application of Concepts Q1. [AS5] Sunitha and her brother Bharat study in the same school. Sunitha walks to the school while Bharath cycles to the school. So, Sunitha has to leave before Bharath to reach the school on time. Graph 10 shows the graph lines of their journey from their home to the school. Look at the graph and answer the following questions. [Refer to TB page 181 Q3] SESSION 2. GRAPHS OF OBJECTS MOVING AT DIFFERENT UNIFORM S... 70

i. Which graph line shows Sunitha’s journey? ii.Whose graph line has a greater slope? iii.Whose speed is greater? iv.If Sunitha wants to reach school in 3 hours at what speed should she walk? A. i. The graph line A shows Sunitha’s journey. ii.The graph line B which belongs to Bharat has a greater slope because greater the angle that the graph line makes with X–axis, greater is the slope. iii.The faster the speed of uniform motion the greater will be the slope of the graph line. Since, Bharat’s graph line has greater slope he is travelling at greater speed. SESSION 2. GRAPHS OF OBJECTS MOVING AT DIFFERENT UNIFORM S... 71

iv. Time = 3 hours Distance from home to school = 10 km (from Graph–10) Speed = Distance traveled Time taken Speed = 10 km 3h Speed = 3.33 km/h SESSION 2. GRAPHS OF OBJECTS MOVING AT DIFFERENT UNIFORM S... 72

SESSION 3 GRAPHS OF STATIONARY OBJECT AND NON-UNIFORM MOTION 3.1 Mind Map 3.2 Terminology i. Non uniform motion – The motion in which there is increase or decrease in speed is called non uniform motion. ii. Stationary object – An object is said to be stationary, if it does not change its position with respect to its surroundings with the passage of time. SESSION 3. GRAPHS OF STATIONARY OBJECT AND NON-UNIFORM MOTION 73

3.3 Key Concepts i. When an object stops at a place, the time increases but the total distance covered remains same. ii. If an object is at rest then the time –distance graph will be line parallel to X–axis. iii.In the graph of motion continuous increase in speed is represented by a curved line. 3.4 Reﬂection on Concepts Q1. [AS5] Look at graph –9. [Refer to TB page 180 Q1] Which section of graph 9 has the greatest slope? What can you say about the speed in this section? What can you say about the speed in section CD of the graph? SESSION 3. GRAPHS OF STATIONARY OBJECT AND NON-UNIFORM MOTION 74

A. The section BC of the graph has the greatest slope. The speed of this section is the greatest because greater the slope greater is the speed. We can see that the section CD is parallel X–axis. From this we can conclude that the object is stationary during this period. Therefore, the speed in the section CD of the graph is zero. SESSION 3. GRAPHS OF STATIONARY OBJECT AND NON-UNIFORM MOTION 75

SESSION 4 REAL LIFE APPLICATIONS OF GRAPHS 4.1 Mind Map 4.2 Terminology i. Distance = Speed x Time. ii. Journey – An act or instance of traveling from one place to another. 4.3 Key Concepts i. Graphs are often the best way to convey descriptions of real world events in a compact form. ii. A story of a particular journey can be represented in the form of a graph. 4.4 Application of Concepts 76 SESSION 4. REAL LIFE APPLICATIONS OF GRAPHS

Q1. [AS5] A river is 32 km away from Nikitha’s house. There is a hillock on the way. Nikitha left for the river one morning on her bicycle. She reached the hillock after 2 hours, pedaling at a speed of 5 kmph. Since she could not cycle up the slope, she continued on foot, walking for an hour at a speed of 3 kmph, and reached the top of the hillock. From there the road was all downhill. She rode her bicycle at a speed of 18 kmph and reached the bottom of the hillock in half an hour. She then rested under a tree for half an hour. Refreshed after a rest she cycled at a speed of 5 kmph and reached the river in 2 hours. Draw a graph of Nikitha’s journey from her home to the river. [Refer to TB page 181 Q2] A. Let us ﬁrst ﬁnd the distance covered in all the time intervals. 77 i. Nikitha pedaled for 2 hours at a speed of 5 kmph. Distance covered = 2 x 5 = 10 km ii. Nikitha walked for an hour at a speed of 3 kmph. Distance covered = 3 x 1 = 3 km SESSION 4. REAL LIFE APPLICATIONS OF GRAPHS

iii. Nikitha rode her bicycle at a speed of 18 kmph and reached the bottom in half an hour. Distance covered = 18 x ½ = 9 km iv. Nikitha rested under a tree for half an hour. Distance covered = 0 x ½ = 0 km v. Nikitha cycled at a speed of 5 kmph and reached the river in 2 hours. Distance covered = 5 x 2 = 10 km Entering the data into table. Time Distance covered (in hours) (in kilometers) 0 0 10 2 13 3 22 3.5 22 4 32 6 Graph is drawn according to the table. SESSION 4. REAL LIFE APPLICATIONS OF GRAPHS 78

4.5 Higher Order Thinking Skills Q1. [AS7] Graph 11 shows the journey of Rakesh and Share Khan. Write a story about their journey on the basis of the graph? [Refer to TB page 181 Q4] SESSION 4. REAL LIFE APPLICATIONS OF GRAPHS 79

A. Answers may vary from student to student. Hints: 1. Take one graph line as Rakesh’s journey and observe the distance covered per unit time. 2. Take the other graph as Share khan’s journey and observe the distance covered per unit time. 3. Students can narrate their story in relation to distance covered, direction of movement etc. Answers for Multiple Choice Questions [Refer TB page 182] 1. b) 2. a) 3. d) 4. d) 5. a) SESSION 4. REAL LIFE APPLICATIONS OF GRAPHS 80

—— CCE Based Practice Questions —— AS1-Conceptual Understanding Very Short Answer Type Questions 1. Fill in the blanks. [Refer to Session 12.4 ] (i) are often the best way to convey descriptions of real world events in a compact form. (ii) A story of a particular journey can be in the form of a graph. 2. State true or false. [Refer to Session 12.3 ] (i) In the graph of motion, continuous increase in speed is represented by a straight line. [] (ii) When an object stops at a place, the time increases but the total distance covered remains same. [] 3. Fill in the blanks. [Refer to Session 12.2 ] (i) The faster the speed of uniform motion, will be the slope of the graph line. 4. Fill in the blanks. [Refer to Session 12.1 ] (i) A is a diagrammatic representation of an area of land or sea showing physical features, cities, roads, etc. (ii) A is a diagram showing the relation between variable quantities, typically of two variables, each measured along one of a pair of axes at right angles. CHAPTER 12. GRAPHS OF MOTION 81

Short Answer Type Questions 5. Answer the following questions in 3-4 sentences. (i) [(Session 12.3)] Distinguish between uniform and non uniform motion. (ii) [(Session 12.3)] Distinguish between rest and motion. (iii) [(Session 12.3)] A car moves with a speed of 40 km/h for two hours. What is the total distance covered by the car? CHAPTER 12. GRAPHS OF MOTION 82

6. Answer the following questions in 3-4 sentences. (i) [(Session 12.2)] What is non–uniform motion? Give an example. 7. Answer the following questions in 3-4 sentences. (i) [(Session 12.1)] Deﬁne Motion. Give an example. CHAPTER 12. GRAPHS OF MOTION 83

(ii) [(Session 12.1)] The distance travelled by a bus in 2 hours is 24 km. Calculate the speed of the car. (iii) [(Session 12.1)] What is the formula for Average speed? AS2-Asking questions and making hypothesis . Very Short Answer Type Questions 8. Fill in the blanks. [Refer to Session 12.1 ] (i) Two graphs can be compared visually only if they have the same CHAPTER 12. GRAPHS OF MOTION 84

Short Answer Type Questions 9. Answer the following questions in 3-4 sentences. (i) [(Session 12.3)] What do the following graphs indicate about the motion of the body? Graph - a Graph - b 10. Answer the following questions in 3-4 sentences. (i) [(Session 12.2)] The ﬁgure given below shows the distance–time graph for the motion of three cars P, Q and R. Shanti wanted to ﬁnd which one of them is moving fastest? Can you guess the questions rose in her mind? Write them. CHAPTER 12. GRAPHS OF MOTION 85

Long Answer Type Questions 11. Answer the following questions in 6-8 sentences. (i) [(Session 12.3)] Can the distance–time graph be a line parallel to Y–axis? Draw such a graph and give reasons for your answer. CHAPTER 12. GRAPHS OF MOTION 86

AS3-Experimentation and ﬁeld investigation Long Answer Type Questions 12. Answer the following questions in 6-8 sentences. (i) [(Session 12.4)] Design and conduct an experiment to test the fastest of three toy cars. Record the distance covered and time taken by each car into a table. Plot a distance–time graph for the three on the same graph. CHAPTER 12. GRAPHS OF MOTION 87

AS4-Information skills and projects Long Answer Type Questions 13. Answer the following questions in 6-8 sentences. (i) [(Session 12.4)] Collect pictures from various sources like internet, magazines, news papers, etc, to illustrate graphs of motion and stick it in your book. CHAPTER 12. GRAPHS OF MOTION 88

AS5-Communication through drawing and model making Short Answer Type Questions 14. Answer the following question in 3-4 sentences. (i) [(Session 12.4)] The graph below shows the race between two athletes running a 100m race. Look at the graph and describe the complete race between the two athletes. CHAPTER 12. GRAPHS OF MOTION 89

Long Answer Type Questions 15. Answer the following question. (i) [(Session 12.4)] An athlete is training herself for a marathon. She runs at constant speed for 2 minutes and then she rests for 1 minute. She repeats this four times. For each minute that she is running she covers 400 m. Plot her training on a distance – time graph. Time 2 3 5 6 8 9 11 12 (in min- utes) Distance 800 800 1600 1600 2400 2400 3200 3200 (in me- ters) CHAPTER 12. GRAPHS OF MOTION 90

16. Answer the following question. (i) [(Session 12.3)] Look at the graph given below. It shows how three runners ran a 100 meter race. Using the information given in the graph, answer the following questions. a. Which runner won the race? Explain your answer. 91 CHAPTER 12. GRAPHS OF MOTION

b. Which runner stopped during the race for rest? c. How long did he stop for rest? Explain you answer. d. How long did Tejesh take to complete the race? 17. Answer the following question. (i) [(Session 12.1)] Draw the distance – time graph for the data given below: Time (in 2 4 6 8 10 12 14 16 18 minutes) 4 8 12 16 20 24 28 32 36 Distance trav- elled (in km) CHAPTER 12. GRAPHS OF MOTION 92

CHAPTER 12. GRAPHS OF MOTION 93

AS6-Appreciation and aesthetic sense, Values Short Answer Type Questions 18. Answer the following questions in 3-4 sentences. (i) [(Session 12.4)] How do you appreciate the role of motion graphs in our daily life? CHAPTER 12. GRAPHS OF MOTION 94

Long Answer Type Questions 19. Answer the following questions in 6-8 sentences. (i) [(Session 12.3)] “Graphs are often the best way to convey descriptions of real world events in a compact form”. How do you support this statement? Explain. AS7-Application to daily life, concern to bio diversity 95 Long Answer Type Questions CHAPTER 12. GRAPHS OF MOTION

20. Answer the following questions in 6-8 sentences. (i) [(Session 12.4)] Radha needs to reach the chicken farm to collect eggs for her store. The egg farm is 30 km away from the store. There is a hill on the way. Radha left for the farm on her bicycle. Radha cycles uphill for 2 hours travelling across 12 kilometers, away from the store and reaches the top of the hill. As she gets tired after cycling she stops to rest for half an hour. From there the road is down hill. She cycles downhill for 18 kilometers in an hour and reaches the farm. Draw a graph of Radha’s journey from her store to the farm. CHAPTER 12. GRAPHS OF MOTION 96

(ii) [(Session 12.4)] Ram and his sister Kajal study at the same school. Ram walks back from school whereas his sister cycles back home. Ram starts walking from school and stops on his way to talk to his friend and then continues back home. Kajal cycled back home using the same route, but did not stop anywhere. The graph below shows the distance–time graph for Ram’s and Kajal’s complete journey from school to their home. Look at the graph and answer the questions that follow. a. How far did Ram walk during the ﬁrst 10 minutes of his journey? b. How long did Ram stop to talk to his friend? c. Write down the distance that Ram had walked when Kajal cycled past him. d. Calculate Ram’s average speed for the complete journey. CHAPTER 12. GRAPHS OF MOTION 97

e. Calculate Kajal’s average speed for the complete journey. 21. Answer the following questions in 6-8 sentences. (i) [(Session 12.2)] Varun and his sister Shreya go to school on their bicycles. Both of them start at the same time from their home but take different times to reach the school even though they follow the same path. The table below shows the distance travelled by them in different time intervals. CHAPTER 12. GRAPHS OF MOTION 98

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