Force and Energy 5

1. Force (फोर्स) — बल

2. Push (पुश) — धक्का

3. Pull (पुल) — खींचना

4. Object (ऑब्जेक्ट) — वस्तु

5. Motion (मोशन) — गति

6. Stationary (स्टेशनरी) — स्थिर

7. Direction (डायरेक्शन) — दिशा

8. Shape (शेप) — आकार

9. Size (साइज़) — माप

10. Speed (स्पीड) — वेग

11. Muscular Force (मस्कुलर फोर्स) — पेशीय बल

12. Gravitational Force (ग्रैविटेशनल फोर्स) — गुरुत्वाकर्षण बल

13. Frictional Force (फ्रिक्शनल फोर्स) — घर्षण बल

14. Elastic Force (इलास्टिक फोर्स) — प्रत्यास्थ बल

15. Mechanical Force (मैकेनिकल फोर्स) — यांत्रिक बल

16. Buoyant Force (बॉयंट फोर्स) — उत्प्लावन बल

17. Upthrust (अपथ्रस्ट) — ऊपर की ओर बल

18. Gravity (ग्रैविटी) — गुरुत्व

19. Friction (फ्रिक्शन) — घर्षण

20. Deform (डिफॉर्म) — विकृत होना

21. Simple Machine (सिंपल मशीन) — सरल मशीन

22. Lever (लीवर) — उत्तोलक

23. Fulcrum (फुलक्रम) — आधार बिंदु

24. Load (लोड) — भार

25. Effort (एफर्ट) — प्रयास

26. Inclined Plane (इन्क्लाइंड प्लेन) — तिरछा तल

27. Ramp (रैम्प) — ढलान

28. Pulley (पुली) — चरखी

29. Rope (रोप) — रस्सी

30. Bucket (बकेट) — बाल्टी

31. Fixed Pulley (फिक्स्ड पुली) — स्थिर चरखी

32. Movable Pulley (मूवेबल पुली) — चल चरखी

33. Wheel (व्हील) — पहिया

34. Axle (एक्सल) — धुरी

35. Screw (स्क्रू) — पेंच

36. Nail (नेल) — कील

37. Tool (टूल) — औजार

38. Machine (मशीन) — मशीन

39. Support (सपोर्ट) — सहारा

40. Plank (प्लैंक) — तख्ता

41. Energy (एनर्जी) — ऊर्जा

42. Work (वर्क) — कार्य

43. Mechanical Energy (मैकेनिकल एनर्जी) — यांत्रिक ऊर्जा

44. Kinetic Energy (काइनेटिक एनर्जी) — गतिज ऊर्जा

45. Potential Energy (पोटेंशियल एनर्जी) — स्थितिज ऊर्जा

46. Solar Energy (सोलर एनर्जी) — सौर ऊर्जा

47. Solar Panel (सोलर पैनल) — सौर पैनल

48. Wind Energy (विंड एनर्जी) — पवन ऊर्जा

49. Wind Turbine (विंड टरबाइन) — पवन चक्की

50. Geothermal Energy (जियोथर्मल एनर्जी) — भू-तापीय ऊर्जा

51. Hydropower (हाइड्रोपावर) — जल ऊर्जा

52. Heat Energy (हीट एनर्जी) — ऊष्मा ऊर्जा

53. Fuel (फ्यूल) — ईंधन

54. Coal (कोल) — कोयला

55. Petrol (पेट्रोल) — पेट्रोल

56. Light Energy (लाइट एनर्जी) — प्रकाश ऊर्जा

57. Sunlight (सनलाइट) — सूर्य प्रकाश

58. Sound Energy (साउंड एनर्जी) — ध्वनि ऊर्जा

59. Vibration (वाइब्रेशन) — कंपन

60. Musical Instrument (म्यूजिकल इंस्ट्रूमेंट) — वाद्य यंत्र

61. Electrical Energy (इलेक्ट्रिकल एनर्जी) — विद्युत ऊर्जा

62. Electricity (इलेक्ट्रिसिटी) — बिजली

63. Electric Charge (इलेक्ट्रिक चार्ज) — विद्युत आवेश

64. Wire (वायर) — तार

65. Appliance (अप्लायंस) — उपकरण

66. Fan (फैन) — पंखा

67. Bulb (बल्ब) — बल्ब

68. Tubelight (ट्यूबलाइट) — ट्यूबलाइट

69. Computer (कंप्यूटर) — संगणक

70. Washing Machine (वॉशिंग मशीन) — कपड़े धोने की मशीन

71. Conservation (कंजरवेशन) — संरक्षण

72. Law (लॉ) — नियम

73. Created (क्रिएटेड) — उत्पन्न

74. Destroyed (डिस्ट्रॉयड) — नष्ट

75. Transform (ट्रांसफॉर्म) — रूप बदलना

76. Total Energy (टोटल एनर्जी) — कुल ऊर्जा

77. Increase (इन्क्रीज) — बढ़ना

78. Decrease (डिक्रीज) — घटना

79. Nature (नेचर) — प्रकृति

80. Environment (एनवायरनमेंट) — पर्यावरण

81. Astronaut (एस्ट्रोनॉट) — अंतरिक्ष यात्री

82. Space (स्पेस) — अंतरिक्ष

83. Earth (अर्थ) — पृथ्वी

84. Float (फ्लोट) — तैरना

85. Rubber Band (रबर बैंड) — रबर बैंड

86. Stretch (स्ट्रेच) — खींचना

87. Release (रिलीज़) — छोड़ना

88. Original Position (ओरिजिनल पोजीशन) — मूल स्थिति

89. Swimming Pool (स्विमिंग पूल) — तैराकी तालाब

90. Upward (अपवर्ड) — ऊपर की ओर

91. Cricket Match (क्रिकेट मैच) — क्रिकेट मुकाबला

92. Village Scene (विलेज सीन) — गाँव का दृश्य

93. Well (वेल) — कुआँ

94. Ladder (लैडर) — सीढ़ी

95. Slide (स्लाइड) — फिसलपट्टी

96. Support Point (सपोर्ट पॉइंट) — सहारा बिंदु

97. Rock (रॉक) — चट्टान

98. Rod (रॉड) — डंडा

99. Flagpole (फ्लैगपोल) — झंडे का खंभा

100. Ramp Path (रैम्प पाथ) — ढलान मार्ग

A. Tick (✔) the correct answer

1. We are able to stay on the ground because of
   ✔ (a) gravitational force

2. A screw jack used to lift a car is a
   ✔ (d) screw

3. The most readily available source of energy is
   ✔ (b) solar energy

4. The upward push of water on a floating object is called
   ✔ (a) buoyant force

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B. Fill in the blanks

1. Most simple machines make use of mechanical advantage.
2. There is no gravitational force in space.
3. Simple machines change the direction of applied force.
4. A moving car possesses mechanical energy due to its motion.
5. An inclined plane is a slope which makes work easier.

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C. Change the underlined words to correct these statements

1. A stretched rubber band regains its original position on being released because of elastic force.
2. Geothermal energy is a renewable source of energy.
3. The pulley used for drawing water from a well is a fixed pulley.
4. Simple machines make our work easier and faster.
5. We are able to walk because of frictional force.

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D. Write short answers

1. Name the different types of forces.

Answer:
The different types of forces are gravitational force, frictional force, muscular force, magnetic force and elastic force.

2. What are simple machines?

Answer:
Simple machines are devices that make our work easier by changing the direction or size of force.

3. Why is geothermal energy referred to as a renewable source of energy?

Answer:
Geothermal energy comes from heat inside the Earth, which is continuously produced, so it does not get exhausted.

4. From where does most of the heat energy come?

Answer:
Most of the heat energy comes from the Sun.

5. Name four different forms of energy.

Answer:
Heat energy, light energy, mechanical energy and electrical energy.

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E. Answer these questions

1. What is a lever? On what basis are levers classified?

Answer:
A lever is a simple machine that consists of a rigid bar resting on a fixed point called fulcrum.
Levers are classified into first-class, second-class and third-class levers based on the position of load, effort and fulcrum.

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2. What is an inclined plane? How is it useful for us?

Answer:
An inclined plane is a sloping surface.
It is useful because it helps us lift heavy objects with less effort.

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3. Does a screw join two pieces of wood better than a nail? How?

Answer:
Yes, a screw joins two pieces of wood better than a nail because its threads hold the wood tightly and do not loosen easily.

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4. What does the law of conservation of energy state?

Answer:
The law of conservation of energy states that energy can neither be created nor destroyed, it can only change from one form to another.

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5. How is wind energy more environment-friendly than heat energy?

Answer:
Wind energy does not cause pollution and does not release harmful gases, while heat energy from fuels causes air pollution.

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Chapter 11 : Force and Energy

Aims

• To know different types of forces.
• To identify the types of simple machines commonly used.
• To learn about the different types of energy.

Force

Force means a push or a pull. When we push or pull an object, we apply force on it.

Force can:

• Move a stationary object
• Stop a moving object
• Increase the speed of a moving object
• Slow down a moving object
• Change the direction of a moving object
• Change the shape and size of an object

Types of Forces

• Muscular Force – Force applied by our muscles while pushing, pulling or lifting.
• Gravitational Force – Force by which the earth pulls objects towards it.
• Frictional Force – Force that slows down moving objects.
• Elastic Force – Force produced when a stretched object returns to its original shape.
• Mechanical Force – Force used by simple machines.
• Buoyant Force – Upward force exerted by water on floating objects.

Simple Machines

Simple machines make our work easier by changing the direction or amount of force.

• Lever
• Inclined Plane
• Pulley
• Wheel and Axle
• Screw

Levers

A lever has three parts:

• Fulcrum – Point of support
• Load – Weight to be lifted
• Effort – Force applied

Types of levers:

• First-class lever – Fulcrum between load and effort
• Second-class lever – Load between fulcrum and effort
• Third-class lever – Effort between fulcrum and load

Energy

Energy is the ability to do work. Energy is present everywhere in nature.

Forms of Energy

• Mechanical Energy – Energy due to motion or position
• Solar Energy – Energy from the sun
• Geothermal Energy – Heat energy from inside the earth
• Wind Energy – Energy from moving air
• Hydropower – Energy from water
• Heat Energy – Energy used for heating and cooking
• Light Energy – Energy from light sources
• Sound Energy – Energy produced by vibrations
• Electrical Energy – Energy due to flow of electric charges

Law of Conservation of Energy

Energy can neither be created nor destroyed. It can only be changed from one form to another.

Force and Energy – Questions & Answers

1. What is force?

Force is a push or pull on an object. It can move, stop, change speed, or change the shape of an object.

2. Name the different types of forces.

Muscular force, Gravitational force, Frictional force, Elastic force, Mechanical force, Buoyant force.

3. What is a simple machine?

A simple machine is a tool that makes work easier by changing the direction or amount of force applied. Examples: lever, inclined plane, pulley, wheel and axle, screw.

4. Explain a lever with examples.

A lever has a fulcrum (support), a load (weight to lift), and an effort (force applied). Examples: scissors, pliers, rod lifting a rock.

5. How are levers classified?

First-class lever: fulcrum between load and effort. Second-class lever: load between fulcrum and effort. Third-class lever: effort between fulcrum and load.

6. What is an inclined plane?

An inclined plane is a slope that helps to raise or lower objects easily. Examples: ramps, slides, planks used for trucks.

7. What is a pulley and its types?

A pulley is a wheel with a groove for a rope. Types: fixed pulley (changes direction of force), movable pulley (reduces effort).

8. What is mechanical energy?

Mechanical energy is the energy an object has due to its motion or position. Examples: moving car (kinetic energy), stretched bow (potential energy).

9. Name other forms of energy.

Solar energy, Geothermal energy, Wind energy, Hydropower, Heat energy, Light energy, Sound energy, Electrical energy.

10. State the law of conservation of energy.

Energy cannot be created or destroyed; it can only change from one form to another. The total energy of an object remains constant.

MCQs

2. The rabies virus is carried by:

• c. Dogs

3. For putting out a fire caused by petrol, we should:

• d. Throw lots of sand on it

4. Nail polish, naphthalene balls and paints may contain:

• c. Poison

Fill in the blanks

1. When the skin is cut by a rusted object, the injection one must take is called a ______.

Antitetanus injection

2. ______ causes swelling and sometimes discolouration of the skin.

Sprains

3. An easily available object like sheets of newspaper or a pillow can be used as ______ to give support to a broken bone.

Splint

4. If a fire is caused by an electrical gadget, do not throw ______ on it.

Water

5. Destroy all things which have crossed their ______.

Expiry dates

Short Answer Questions

1. What is a tourniquet?

A tourniquet is a tight band used to stop bleeding from a limb.

2. Which articles could be used as a splint in case of a fracture?

Objects like sticks, newspapers, cardboard, or pillows can be used as a splint.

3. What is a sling?

A sling is a bandage used to support an injured arm or shoulder.

4. Name the disease caused by a virus carried by dogs and cats.

Rabies

5. When someone's clothes catch fire, we must not let him run around in panic. Why?

Running spreads fire faster and increases burns. The person should stop, drop, and roll to put out the fire.

Answer These Questions

1. What first aid should be given in case of a minor wound?

Wash the wound with clean water, apply antiseptic, and cover it with a sterile bandage.

2. How would you help someone with a bleeding nose?

Sit the person down, lean the head slightly forward, pinch the nose for 10 minutes, and apply a cold compress on the nose.

3. What is a splint? How and why should it be used?

A splint is a rigid support to immobilize a fractured or injured limb. It prevents further injury and reduces pain.

4. We must not prick blisters. Why?

Pricking blisters may cause infection and delay healing.

5. How will you put out a fire caused by defective wiring?

Do not use water. Switch off electricity and use sand, fire extinguisher, or a fire blanket to put out the fire.

6. What first aid should be given in case of an animal bite?

Wash the wound with soap and water, apply antiseptic, and take a tetanus injection if required. Consult a doctor for rabies vaccination.

HOTS Questions

1. Why should we remain calm when helping someone whose clothes have caught fire?

Remaining calm prevents panic, allows safe extinguishing of fire, and reduces injury.