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Chapter Review:

 

• Cycle, bus, car, bull cart, train, boat, ship, aeroplane and helicopter are the main means of transport. 
• Cycle, moterbike, car, bus and train are the means of the road transport.
• Helicopter, jet aircraft, aeroplane are the means of air transport.
• Boat, steamer, ship are the means of water transport.
• The fixed quantity of measurement is called unit. 
• The SI unit of length is a metre (m).
• The full form of SI unit is International System of unit. 
• The magnitude of measuring is expressed into two parts i.e (i) Numerical part (ii)  Unit part.
• The length of a foot, the width of a finger, and the distance of a step are the ancient ways of measuring length. 
• The modern ways of measuring length are milimetre, centimetre, metre and kilometre etc. 
• Milimetre, centimetre  and metre are used to measure the small distances while kilometre for long distances.
• 1 kilometre is equal to 1000 metres.
• 100 centimetres are equal to 1 metre.
• There are 10 milimetres in 1 centimetre.
• There should be used a thread for measuring the curve line then thread is measured by scale. 
• The changing in position of an object along with time is known as motion.
• There are following types of motions: rectilinear motion, circular
  motion, periodic motion and rotational motion etc. 
• When the objects move along a straight line. This type of motion is called rectilinear motion.
• When an object maintains a fixed distance from a fixed point during motion such a motion is known as circular motion. 
• When an object repeats its motion after a fixed time of interval such a motion is known as periodic motion. 
• When an object moves on its axis is called rotational motion. 

 

Text book Exercise: 

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Q1: Give two examples each, of modes of transport used on land, water and air.

Ans: Two examples of each.

Land transport: bus and train.

Water transport: boat and   ship.

Air transport: Helicopter and aeroplane. 

Q2: Fill in the blanks:
(i) One metre is ______________ cm.
(ii) Five kilometre is ______________ m.
(iii)Motion of a child on a swing is ______________.
(iv) Motion of the needle of a sewing machine is ______________.
(v) Motion of wheel of a bicycle is______________.

Ans: 

(i) 100

(ii)  500

(iii) periodic motion

(iv) periodic motion

(v)  rotational motion

Q3:  Why can a pace or a footstep not be used as a standard unit of length?

Ans: Standarrd unit of length must have a fixed numeric value while footstep does have so. 

Q4: Arrange the following lengths in their increasing magnitude:
1 metre, 1 centimetre, 1 kilometre,1 millimetre.

Ans: 1 milimetre, 1 centimetre, 1 metre, 1 kilometre

Q5: The height of a person is 1.65 m. Express it into cm and mm.

Ans: 

The height of a person = 1.65 m 

         In centimetre, 

           1 metre = 100 cm 

           1.65 m = 1.65 x 100 cm 

                           = 165 cm 

          In milimetre, 

           1 centimetre = 10 milimetre

           1 metre = 100 centimetre

           Or        = 100 x 10 milimetre 

                      = 1000 milimetre

            1.65 metre = 1.65 x 1000 milimetre

                            = 1650 milimetre          

Q6: The distance between Radha's home and her school is 3250 m. Express this distance into km.

Ans:

          

Q7: While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?

Ans:

Reading of scale at one end = 3.0 cm

Reading of scale at other end = 33.1 cm

Distance between two end = 33.1 - 3.0 cm

                                           = 30.1 cm

 

Q8: Write the similarities and differences between the motion of a bicycle and a ceiling fan that has been switched on.

Ans: Similarities: the motion of a bicycle and a celing fan both have circular motion. Differences: The bicycle moves on straight line but ceiling fan does not move so. 

Q9: Why could you not use an elastic measuring tape to measure distance? What would be some of the problems you would meet in telling someone about a distance you measured with an elastic tape?

Ans:

Q10: Give two examples of periodic motion.

Ans:

(i) The motion of child on a swing.

(ii) moving here and there the branches of tree.

 

 

 

 

Important Questions With solutions: 

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Q1: Define unit.

Ans: Measurement means the comparison of an unknown quantity with some known quantity. This known fixed quantity is called a unit.

Q2: What is S. I unit ?

Ans: The system of units now used is known as the International System of Units (SI units).

Q3: Write the SI unit of length.

Ans: The SI unit of length is a metre.

Q4: Write the full form of S. I Unit.

Ans: International System of Units (SI units)

Q5: What is periodic motion?

Ans: An object or a part of it repeats its motion after a fixed interval of time. This type of motion is called periodic motion.

Q6: Give three examples of periodic motion.

Ans:

(i)   Motion of a pendulum, 

(ii)   a branch of a tree moving to and fro,

(iii)    motion of a child on a swing,

Q7: What is motion?

Ans: The changing in position of an object along with time is called motion.

Q8: What is rectilinear motion?

Ans: The objects move along a straight line. This type of motion is called rectilinear motion.

Q9: What is circular motion?

Ans: When an object moves along the circular path like a stone, the distance of the stone from your hand remains the same. Such type of motion is called circular motion. Ex. –

Q10: Give two example of circular motion.

Ans:  (i)  The motion of a point marked on the blade of an electric fan (ii)  the hands of a clock are examples of circular motion.

Q11: Which vehicle is used to travel or transport from the Earth to other planets?

Ans: spacecraft.

Q12: Name few means of transport available in ancient times before the invention of wheel.

Ans: Boats and domestic animals.

Q13: Which invention made a great change in modes of transport?

Ans: invention of the wheel.

Q14: Which invention introduced a new source of power?  

Ans: The invention of steam engine introduced a new source of power.

Q15: Name some commonly used units of measurements in ancient times.

Ans: The length of a foot, the width of a finger, and the distance of a step, a handspan and a cubit.

Q16: How do you decide whether an object is in motion or at rest?

Ans: If a body changes its position with respect to its surroundings, it is said to be in motion, and if it does not change its position with respect to its surroundings, it is at rest.

Q17: How can we decide that how fast or slow a motion is.

Ans: Motion is a change in the position of an object with time. The change in this position can be determined through distance measurements. This allows us to know how fast or slow a motion is. The movement of a snail on the ground, an aeroplane flying high up in the air fast

Q18: Name the S.I. unit of length.

Ans: Metre is the unit of length in SI unit.

Q19: The ball is rolling on the ground – Name the type of motion exhibited by it.

Ans: the ball undergoes a rectilinear motion as well as rotational motion.

Q20: What do you mean by measurement?

Ans: Measurement means the comparison of an unknown quantity with a known quantity.

Q21: When is the motion of a body said to be rectilinear ,circular, periodic ?

Ans:

When objects move along a straight line, the type of motion they possess is rectilinear motion.

When the distance of the object from the centre remains the same, the type of motion It possesses is circular motion.

When an object or a part of it repeats its motion after a fixed interval of time, the type of motion It possesses is periodic motion.