Subrat Sir - TTRC Rayagada

1) A body, when acted upon by a force of 10 kgf, gets displaced by 0.5 m. calculate the work done by the force, when the displacement is (i) in the direction of force, (ii) at an angle of 60 with the force, and (iii) normal to the force.

2) A body of mass 40 kg climbs up the stairs and reaches the roof at a height 8 m in 5 s. Calculate : (i) the force of gravity acting on the body (ii) the work done by him against the force of gravity (iii) the power spent by the boy. (Take g = 10 m s^-2)

3) A man spends 6.4 kJ energy in displaying a body by 64 m in the direction in which he applies force, in 2.5s. Calculate: (i) the force applied, and (ii) the power spent (in H.P.) by the man.

4) A weight lifter lifted a load of 200 kgf to a height of 2.5m in 5s. Calculate : (i) the work done, and (ii) the power developed by him. Take g = 10 N kg^-1.

5) A machine rises a load of 750 N through a height of 16 m in 5 s. Calculate : (i) the energy spent by the machine (ii) the power of machine if it is 100 % efficient.

6) An electric heater of power 3 kW is used for 10 h. How much energy does it consume? Express your answer in (i) kWh, (ii) joule.

7) A water pump raises 50 litre of water through a height of 25m in 5 s. Calculate the power of the pump required. (Take g = 10 N Kg^-1 and density of water = 1000 kg m^-3)

8) A pump is used to lift 500 kg of water from a depth of 80 m in 10 s. Calculate : (a) The work done b the pump (b) the power at which the pump works, and (c) the power rating of the pump if its efficiency is 40% (take g=10 m s-2)  [ Hint : Efficiency =  ]

9) An ox can apply a maximum force of 1000 N. It is taking part in a cart race and is able to pull the cart at a constant speed of 30 m s^-1 while making its best effort. Calculate the power developed by the ox.

10) The power of a motor is 40 kW. At what speed can the motor raise a load of 20000 N ?

11)  Rajan exerts a force of 150 N in pulling a cart at a constant speed of 10 m s^-1. Calculate the power exerted.

12) A boy weighing 350 N climbs up the 30 steps each 20 cm high in 1 minute. Calculate : (i) the work done, and (ii) the power spent.

13) It takes 20 s for a person A of mass 50 kg to climb up the stairs, while another person B of same mass does the same in 15 s. Compare the (i) work done, and (ii) power developed by the person A and B.
Ans: As person A and B has same mass and climb same height against the gravity, therefore the work done (W) by them is same.

14) A body of weight 40 kgf climbs up the 15 steps, each 15cm high in 10s and a girl of weight 20 kgf does the same in 5s. Compare the (i) work done, and (ii) the power developed by them. Take g = 10 N kg^-1.

15) A man raises a box of mass 50 kg to a height of 2m in 20 s, while another man rises the same box to the same height in 50 s. (a) compare : (i) the work done, and (ii) the power developed by them.
(b) Calculate : (i) the work done, and (ii) the power developed by each man. Take g = 10 N Kg^-1.

16) A boy takes 3 minutes to lift a 20 litre water bucket from a 20m deep well, while his father does it in 2 minutes. (a) compare : (i) the work, and (ii) power developed by them. (b) How much work each does? Take density of water = 10³ kg m^-3 and g = 9.8 N kg^-1.

For Answer’s see below :

[embeddoc url=”http://subratsir.ttrc.in/wp-content/uploads/2017/02/Work_energy_power_icse_10_numerals.pdf” viewer=”google” download=”no”]

[embeddoc url=”http://subratsir.ttrc.in/wp-content/uploads/2017/01/Static-Electricity.pdf” viewer=”google” download=”no”]

[embeddoc url=”http://subratsir.ttrc.in/wp-content/uploads/2017/01/Circles.tif” download=”all”]

Check your progress :

1. Choose the most appropriate answer.
2. Which of the following has the least inertia?
   pencil b. School bag     c.Book  d. TableAns. Pencil because it has less mass.
3. If A and B are two objects with masses 6 kg and 34 kg respectively then,
   A has more inertia than B b. B has more inertia than A
   c. A and B have the same inertia c. none of the two has inertiaAns. B has more inertia than A because B has more mass than A
4. Newton’s first law of motion is also called the
   law of momentum b. law of mements
   c. law of inertia (ans)                      d. law of mases
5. A passenger in a bus tends to fall backward when the bus starts suddenly due to the
   inertia of rest (ans) b. inertia of motion
   c. inertia of direction      d. none of these
6. A cyclist does not come to rest immediately after he stops paddling due to the
   inertia of rest b. inertia of motion (ans)
   c. inertia of direction      d. none of these
7. Answer these questions
   1. State Newton’s first law of motion.
      Ans: Newton’s first law of motion states that “Every body continues to be in its state of rest or of uniform motion in a straight line unless it is compelled by some external force to change that state.
   2. Explain with an example that a body at rest will remain at rest unless some external force acts upon it to change its state of rest.
      Ans: We observe in our daily life that an object lying anywhere keeps on lying there only unless someone moves it from there. For example a chair, a table, a bed etc.
   3. Exaplin with an example that body continues to move along the same straight line unless some external force acts upon it to change its direction of motion.
      Ans: A cyclist riding along a road does not come to rest immediately after he stops paddling. The bicycle continues after he stops paddling. The bicycle continues to move forward due to the inertia of motion. But eventually it comes to rest as a result of the retarding action of motion.
   4. Define inertia on the basis of Newton’s first law of motion. Give a suitable example also.
      Ans: A body on its own cannot change its state of rest or state of uniform motion alonf a straight line. This inability of a body to change by itself its state of rest or of uniform motion along a straight line is called inertia of the body.
      Given below is a simple example to demonstrate the property of inertia.
      Take an empty and dry glass tumbler. Place a square piece of thick, smooth card over the mouth of the glass. Place a coin at the center of the card.
      b. now, flick the card horizontally striking it hard with your finger. The card piece flies away and the coin falls into the glass.
      Explanation : Initially both the card and coin are at rest. When the card is flicked, it comes into motion. The coin, however, remains at rest due to the inertia of rest. As a result, only the card flies away and the coin falls into the glass tumbler.
   5. Establish the relationship between mass and inertia. Give an example.
      A heavier body has more inertia than a lighter body. Therefore we can say that ‘more the mass, more is the inertia and lesser the mass, lesser is the inertia of a body’. For example a large and heavy trolley shows a greater resistance to change its state of rest or of uniform motion than a small and lighter object like a toy car.
   6. Give two examples to show that greater the mass, greater is the inertia of the body.
      Example-1. Mass of a train is more than the mass of a bicycle. So train has the more inertia than a bicycle.
      Example-2. A toy car has less mass than an original car so the toy car has less inertia than an original car.
   7. Write an experiment to demonstrate the property of inertia.
      Given below is a simple experiment to demonstrate the property of inertia.
      a. Take an empty and dry glass tumbler. Place a square piece of thick, smooth card over the mouth of the glass. Place a coin at the center of the card.
      b. now, flick the card horizontally striking it hard with your finger. The card piece flies away and the coin falls into the glass.
      Explanation : Initially both the card and coin are at rest. When the card is flicked, it comes into motion. The coin, however, remains at rest due to the inertia of rest. As a result, only the card flies away and the coin falls into the glass tumbler.
   8. Define the term the inertia of rest.
      A body at rest remains at rest and cannot start moving on its own. This inherent property of body to resist any change in its state of rest is called inertia of rest.
   9. Explain the following by giving suitable reasons:
      • A passenger in a bus tends to fall backward when it starts suddenly.
        When the bus starts suddenly, the lower part of the passenger’s body starts moving forward with the bus. But the upper part of the body tends to remain in the state of rest due to inertia of rest. As a result, the passenger falls backward.

1. Dust can be removed from a hanging carpet by shaking it or by beating it with a stick.
   Ans: Both the carpet and the dust are at rest. When the carpet is shaken or beaten with a stick, the carpet is set into motion while the dust remains in the state of rest due to inertia of rest. Thus the dust comes out side and falls down due to the pull of gravity.
2. A bullet fired against a glass window pane makes a hole in it without cracking it.
   Ans: Initially the entire glass is in the state of rest. When a bullet strikes a glass plane, the part of the glass pane which comes in contact with the bullet immediately shares the large velocity of the bullet and flies away making a hole. The remaining part of the glass, due to inertia of rest, remains at rest and is not cracked.
3. A passenger in a moving bus tends to fall backward when it stops suddenly.
   Ans: When the bus stops suddenly, the lower part of the passenger’s body comes to rest along with the bus. The upper part of his body tends to remain in the state of motion due to it’s inertia of motion. As a result the passenger leans forward.
4. A person jumping out of a speeding bus may get seriously injured.
   Ans: When the passenger jumps out of a speeding bus, the lower part of the person’s body comes to rest on touching the ground. The upper part of his body tends to remain in the state of motion due to its inertia of motion. As a result, the person jumping out of the speeding bus falls forward and get seriously injured.
5. An athlete runs a certain distance before taking a long jump.
   Ans:The velocity acquired by running is added to the velocity of the athlete at the time of jump. Hence. He can jump over a longer distance due to increased inertia of motion.

1. Q) What is a grid?

A: A grid is a set of horizontal and vertical lines that criss-cross each other and form a network.

 

1. Q) Define the terms: parallels of latitude and meridians of longitude.

A: A set of imaginary circular lines drawn horizontally between the two poles and parallel to the Equator and to each other are called parallels of latitude.  They run in an east-west direction. Another set of imaginary lines drawn vertically from the North Pole to the South Pole are called meridians of longitude.

 

1. Q) What is the 0^olatitude referred to us?

A: The Equator, being the starting point, is considered to be 0^o latitude. The angular distance of either of the poles from the Equator is 90^o. Therefore, the North Pole is marked as 90^oN Latitude while the south Pole is marked as 90^oS latitude.

 

1. Q) What is the Greenwich Mean Time?
2. Q) Define heat zone?

A: Since the earth is spherical, the rays of the sun become more and more slanting as we move away from the equator and towards the poles. Direct rays give more heat than slanting rays. The Earth can be divided into three zones on the basis of the amount of heat received from the Sun. These are the heat zones.

 

1. Q) What is the distance between two degrees of longitude?

A: The distance between two degrees of longitude is 111 km.

 

1. Q) What is the importance of local time in daily life?

A: All places located on the same meridian see the sun at the same position in the sky. This is the local time for that meridian.

 

1. Q) What is the differences in and need for time zones?

A: Since the Earth takes 24 hours to complete one rotation, twenty-four time zones of one hour each were demarcated.

 

1. Q) What is the significance of latitudes and longitudes?

A: The latitude of a place is the angular distance of that place north or south of the Equator measured from the centre of the Earth. The longitude is the angular distance of that place east or west of the Prime Meridian. The point of intersection of a parallels of latitude and meridians of longitude gives the exact location of a place.

 

Numerals

1. Q) What is the time and day at a certain place on 30^oW longitude when it is 8 AM on Tuesday at a place 110^oE longitude?

A: 30+110 = 140^o towards west

1 degree = 4 minute

So 140 degree = 140*4 = 560 minutes = 9 hours and 20 minutes

As the place is towards west, so to get the time of place

= 8 AM Tuesday – 9 Hours and 20 Minutes = 10:40 PM Monday

 

1. Q) If a cricket test match starts at Melbourne (145^oE) at 10 AM when shall we, in India, tune in to our television sets to watch it?

A: The longitude of India is 82.5^oE.

145^o – 82.5^o = 62.5^o

We know that 1^o = 4 minutes

So 62.5^o = 62.5 X 4 = 250 minutes

As India is towards west of Melbourne so 250 minutes or 4 hours and 10 minutes will be subtracted from Melbourne time.

So time at India is             = 10 AM – 4 Hours and 10 Minutes

= 5:50 AM

 

1. Q) It is noon at a place when it is 9 AM at Greenwich. Calculate the longitude of that place.

A: The difference of 12 Noon and 9 AM is 3 Hours.

4 minutes = 1 degree

So 3 Hours = 180/4 = 45 degrees

Since 12 Noon is greater than 9 AM so the place is towards east of Greenwich. Means 45^oE

 

1. Q) It is 6 PM at a place 10^oW (S), When it is 1 PM at a certain place (R). Calculate the longitude of R.

A: 6 PM – 1 PM = 5 Hours

4 minutes = 1 degree

So 5 hours = 300 minutes = 300 / 4 = 75 degrees

As 1 PM is less the 6 PM so Place R is towards west of place S

So longitude of place S = 10^oW+75^o = 85^oW

 

Fill up the blanks

1. The point of intersection of a parallel and a meridian gives the exact location of a place.
2. The imaginary line on which our earth rotates is called its
3. The ends of an axis are known as
4. The pole towards the north is called the North Pole and the pole towards the south is called the south pole.
5. The imaginary line that forms a circle around the surface of the Earth and is exactly midway between the two poles and perpendicular to the axis is called
6. The part of the Earth that lies to the north of the Equator is called the Northern Hemisphere and the part to the south is called the southern Hemisphere.
7. The Equator is the longest parallel.
8. The parallel of 23^oN, called the Tropic of Cancer.
9. The parallel of 23^oS, called the Tropic of Capricorn.
10. The parallel of 66^oN, called the Arcatic Circle.
11. The parallel of 66^oS, called the Antarctic Circle.
12. The three heat zones are Torrid zone, Temperate zone, Frigid Zone.
13. The Torrid zone is the hottest zone on the Earth because it receives direct rays of the Sun throughout the year.

1. Q) How do weather and climate influence life ?

A: Weather and climate influences our ways of life- the clothes we wear, the houses we live in, the crops we grow and so on.

 

1. Q) State any three factors that determine the climatic conditions of a geographical location?

A: The factors that determine the climatic conditions of a geographical location are rainfall, temperature, humidity and wind speed.

 

1. Q) Define the following terms: (i) weather and (ii) climate

A: Weather is the condition of the atmosphere at a particular place over a short period of time. Climate refers to the average weather conditions of a large area over a long period of time, say 25 to 30 years.

 

1. Q) What is humidity?

A: The amount of water vapour present in the atmosphere is called humidity.

 

1. Q) What is absolute humidity?

A: It is the actual amount of water vapour in a given volume of air at a given temperature. It is measured in grams per cubic metre.

 

1. Q) What is relative humidity?

A: It is the ratio between the actual amount of water vapour in a given volume of air and the maximum amount of water vapour that the same volume of air can contain at the same temperature. It is expressed in percentage.

 

1. Q) What is a rain gauge used for?

A: Rain gauge is used to measure rainfall. The unit of rainfall is centimeter or milimetre.

 

1. Q) What is precipitation?

A: Continuous condensation of water vapour in the air results in the formation of minute droplets of water. When these droplets join together, they form bigger drops, which become too heavy to float and start falling down. This process is called precipitation.

 

1. Q) List the various forms of precipitation?

A: There are four forms of precipitation : rain, snow, sleet and hail.

 

1. Q) Write the forms of condensation?

A: The forms of condensation are clouds, dew, frost, fog and mist.

 

1. Q) What are clouds?

A: Clouds are extreme small and light accumulations of drops of water or crystals of ice that remain suspended in the air.

 

1. Q) Write types of clouds?

A: Based on their appearance, height at which they occur and their characteristics clouds can be classified as Cirrus clouds, Cumulus clouds, Stratus clouds, Nimbus clouds.

 

1. Q) What is Dew ?

A: Dew is the tiny drops of water formed on exposed objects, such as grass, leaves and plants, during the night.

 

1. Q) What is frost?

A: Frost is ice crystals formed from moisture in the air at temperature below freezing point (0 c or 32 F) that condenses on grass, leaves and plants.

 

1. Q) What is Fog ?

A: Fog is a danse cloud cover that forms very close to the ground or water bodies, instead of in the sky.

 

1. Q) What is Mist?

A: Mist is less intense fog.

 

1. Q) What is rain?

A: When the condensed water vapour in the clouds falls down and is visible to the naked eye in the form of drops of water, it is known as rain.

 

1. Q) What is drizzle ?

A: When the drops of rain are very small, it is called drizzle.

 

1. Q) What are westerly and easterly winds ?

A: The wind gets its name from the direction from which it blows. Winds blowing from the west are called westerly winds and those blowing from the east are called easterly winds. These winds influence rainfall and surface currents of the ocean.

 

1. Q) What is Coriolis effect?

A: The rotation of the Earth makes winds deflect from their original path. This deflection due to the Earth’s rotation is called the Coriolis effect.

 

1. Q) What is Ferrel’s Law?

A: Winds get deflected to their right in the Northern Hemisphere and to their left in the Southern Hemisphere. This is known as Ferrel’s Law.

 

1. Q) What is a Beaufort Scale?

A: A Beaufort Scale, also known as Beaufort Wind Force Scale, is used to measure wind velocity  based on the observed sea conditions.

 

1. Q) List the major pressure belts of the earth.

A: There are four major pressure belts on the Earth as

• The equatorial low pressure belt (5^oN to 5^oS )
• The sub-tropical high pressure belt (30^oN & S to 35^oN & S)
• The sub-polar low pressure belt (60^oN & S to 65^oN & S)
• The polar high pressure belt (90^o N & S)

 

1. Q) What is sunshine hours?

A: The amount of sunshine that a geographical location receives has a direct influence on its temperature. This amount is measured in sunshine hours.

 

Fill Up the Blanks.

 

1. The temperature of the atmosphere can be defined as the degree of hotness or coldness of air.

 

2. The instrument used to measure temperature is called thermometer.

 

3. Scientific study of weather conditions is called meterology .

 

4. Scientists who study weather are called meteorologists.

 

5. The predictions, which are announced by weather stations, are collectively known as weather forecast.

 

6. The difference between the maximum and the minimum temperatures recorded in a year is called the diurnal range of temperature.

 

7. The average of maximum and minimum temperature recorded in a day is mean daily temperature.

 

8. The difference between the maximum and minimum temperature recorded in a year is called the annual range of temperature.

 

9. The average of mean temperature for twelve months is mean annual temperature.

 

10. The freezing point of alcohol is -115^o

 

11. The boiling point of alcohol is 357^o

 

12. The two most commonly used scales to measure temperature are Celcius (^oC) and Farenhite (^oF).

 

13. Weather stations normally use the Stevenson Screen, an instrument shelter, to protect their thermo meters from rain.

 

14. The instrument used to measure the atmospheric pressure is called

 

15. There are two types of barometers : mercury barometer and aneroid barometer.

 

16. The unit of measurement of pressure is milibars (mb).

 

17. The normal pressure at sea level is 1013 mb.

 

18. When pressure is less than 1013 mb it si called low pressure and when more than 1013 mb is called high pressure.

 

19. Horizontal movement of air from one place to another is called

 

20. The instrument used to measure the direction of wind is called a wind vane.

 

21. The anemometer is an instrument used to measure the speed of wind.

 

22. The speed of wind is measured in knots.

 

23. 1 knot = 1 nautical mile/hour.

 

24. Force exerted by a column of air due to its weight, at a particular place on the Earth’s surface is called Atmospheric pressure.

 

25. Weather studies are carried out by ballons and

 

26. Every square inch of our bodies is constantly under pressure from the Earth’s atmosphere with a force of 1kgcm^-2 .

 

27. 1 kg/cm² = 7 lb/in²

 

28. The force on 1000 cm² (a little larger than a square foot) is about a ton!

 

29. Status clouds found above 2000 m of altitude.

 

30. Nimbus clouds found at altitude below 2000m.

 

 

 

 

 

 

Q.1) Who were the Truks?

A: The Turks were nomads who lived in certain areas of northern, eastern, western and central Asia since the 800 CE.

 

Q.2)Name the two notable Turkish rules who invaded India.

A: The Turkish rulers Mahmud of Ghazni and Muhamad Ghori of Ghor invaded the India.

 

Q.3) Why did these Turkish rulers invade India?

A: Mahmud of Ghazni only wanted to acquire wealth that was contained in the various North Indian temples. But Muhamad Ghori aimed at establishing direct rule over conquered territories in India.

 

Q.4) Which Turkish invader of India took on the title of Sultan? Name some important temple cities that were plundered by this ruler.

A: Mahmud of Ghazni took the title of Sultan. The important temple cities like Thaneswar, Mathura, Kannauj and Somnath were plundered by him.

 

Q.5) Which Turkish invader laid the foundation of Islamic rule in India?

A: Muhammad Ghori, also known as Muhammad of Ghor, laid the foundation of Islamic rule in India.

 

Q.6) Who defeated whom in the (i) first battle of Tarain and the (ii) second battle of Tarain?

A:Prithviraj Chauhan defeated Muhammad Ghori in the First Battle of Tarain and Muhammad Ghori defeated Prithviraj Chauhan in the second battle of Tarain.

 

Q.7) Name the ruler who laid the foundation of the Delhi Sultanate in India.

A: Qutbuddin Aibak laid the foundation of the Delhi Sultanate in India.

 

Q.8) State one reason why the Turks were successful in their invasion of India.

A: There are various reasons for the success of the Turks. Their religious zeal was a primary reason. One of Other reasons were : Internal conflict : The regional kingdoms were busy in fighting with each other and could not put up a united front against foreign invasions.

 

Practice Exercises

 

Q.III.1) What was the basic difference in motive between Mahmud of Ghazni and Muhammad Ghori for invading India?

A: Mahmud of Ghazni did not want to establish an empire in India but only wanted to acquire wealth that was contained in the various North Indian temples. Muhammad Ghori aimed at establishing direct rule over conquered territories in India.

 

Q.III.2) What strategy used by Mahmud of Ghazni in each of his expeitions to India ?

A: His campaigns were invariably launched in the hot summer months and on each occasion he would leave India before the onset of the monsoons. This was done so that his troops would not be trapped by the flooded rivers of the Punjab.

 

Q.III.2) Analyse the impact of repeated incursions by Muhmud of Ghazni.

A: The impact of these invasions was the breakdown of Indian resistance, paving the way for future Turkish conquests. It also exposed the inability of the Indian rulers to stand united against external threats.

 

Q.III.3) Explain the circumstances that laid to the establishment of the Delhi Sultanate.

A: After Mohammad Ghori’s death, his empire was divided among his slave generals among whom Qutbuddin Aibak seized the opportunity and laid the foundation of the Delhi Sultanate in India.

Q.III.4) Assess the causes of the success of the Turks in India.

A: The religious zeal was a primary reason for the success of the Turks. Other reasons are i. Internal conflict, ii. Lack of unified command in Rajput army, iii. Superiro military technology of the Turks.

Q.IV.1) Write short notes on main battles fought by Mahmud of Ghazni in India.

A: Mahmud of Ghazni made his first attack on Jaipal. Than jaipal’s son Anandpal alliance with the rulers of Ujjain, Gwalior, Kalinjar, Kanauj, Delhi and Ajmer and fought with him. He attacked and plundered several other cities, such as Nagarkot, Kangra, Thaneswar, Mathura and Kanauj.

Q.IV.2) Mohammad Ghori and the Battles of Tarain.

A: Mohammad Ghori was defeated in 1191 CE in the First Battle of Tarain by Prithviraj Chauhan. The next time he returned with a mightier army that comprised Turkish and Afghani soldiers and fought again with Prithviraj Chauhan in Second Battle of Tarain and defeated Prithviraj.

 

Fill in the blanks

• During the eleventh and twelfth centuries CE, the Turkish rulers invaded the Indian subcontinent.
• Mahmud of Ghazni wanted to acquire wealth that was contained in the various North Indian Temples.
• Muhammad Ghori aimed at establishing direct rule overconquered territories in India.
• Alberuni and Firdausi, renowned Persian poets, were patronized by Mahmud of Ghazni.
• The Turks used horses as opposed to elephants used by Rajputs in warfare.
• Firdausi wrote the famous epic, Shah Namah in Persian.
• Alberuni wrote Kitab al Hind, a historical account, which gave a good account of the polity and society of India on the eve of Mahmud’s invasion.