NCERT Solutions Class 6 Science Chapter 10 Motion and Measurement of Distances

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

Answer:

(i) Modes of Transport used on Land: Cars and Trains

(ii) Modes of Transport used on Water: Ships and Boats

(iii) Modes of Transport used in Air: Airplanes and Helicopters

2. Fill in the blanks:

(i) One metre is _____ cm.
(ii) Five kilometres 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 _____.

Answer:

(i) One metre is 100 cm.

(ii) Five kilometres is 5000 m.

Explanation:

There are 1000 m in 1 km.

Therefore, 5 km = 5 × 1000 m = 5000 m.

(iii) Motion of a child on a swing is periodic.

Explanation: At a certain time interval, the motion of a swing repeats itself. Hence, it is an example of periodic motion.

(iv) Motion of the needle of a sewing machine is periodic.

Explanation: The needle of a sewing machine moves up and down frequently in a certain time interval. Therefore, it is an example of periodic motion.

(v) Motion of the wheel of a bicycle is circular.

Explanation: The wheel of a bicycle rotates about a fixed point as the bicycle moves. Thus, it is an example of circular motion.

3. Why can a pace or a footstep not be used as a standard unit of length?

Answer: The size of the foot is not same of each person. When footsteps of two people are used to measure the length, the two distances may not be equal. Therefore, footstep is not a constant quantity and cannot be used as a standard unit of length.

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

Answer:

On converting all the given measures in millimetres (mm)

1 cm = 10 mm

1 m = 100 cm = 1000 mm

1 km = 1000 m = 100000 cm = 10000000 mm Therefore, the lengths in increasing magnitude can be written as,

1 millimetre < 1 centimetre < 1 metre < 1 kilometre

5. The height of a person is 1.65 m. Express this in cm and mm.

Answer:

Given, height of the person = 1.65 m

As, there are 100 cm in 1 m

Hence, height of the person in centimetres

= 1.65 × 100 cm = 165 cm

There are 1000 mm in 1 m

Hence, height of the person in millimetres

= 1.65 × 1000 mm = 1650 mm.

6. The distance between Radha’s home and her school is 3250 m. Express this distance in km.

Answer:

Given, the distance between Radha's home and her school = 3250 m.

We know that, 1 km = 1000 m

or, 1 m =1/1000 km

Hence, on converting 3250 m into km,

3250 × 1/ 1000 km = 3.25 km.

7. While measuring the length of a knitting needle, the reading of the scale at one end is 3 cm and at the other end is 33.1 cm. What is the length of the needle?

Answer:

Given, reading at first end = 3 cm reading at second end = 33.1 cm

The length of the knitting needle can be calculated by subtracting 33.1 cm by 3 cm.

33.1 cm - 3 cm = 30.1 cm.

Hence, the length of the knitting needle would be 30.1 cm.

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

Answer:

Similarities: The blades of the fan and the wheels of the bicycle are attached at a fixed point. Secondly, both have circular motion about their respective fixed points.

Differences: The blades of the fan have circular motion while the bicycle has linear motion. Secondly, the motion of the blades of a fan is periodic while the motion of a bicycle is rectilinear motion.

9. Why can 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?

Answer: An elastic measuring tape is not a suitable measuring scale because it can be stretched. In this case, the measured length would not be correct. If you measure the length of an object twice using an elastic tape, then you may get different values of the same length.

10. Give two examples of periodic motion.

Answer:

(i) In a simple pendulum, the bob repeats its motion at a certain time interval. This motion is known as periodic motion.

(ii) The motion of a swing repeats its motion at a certain time interval. Thus, a girl sitting on a swing has periodic motion.

Question. Some students conduct an experiment to find out how long different rubber balls would keep bouncing before they stop, when dropped from a fixed height. Which unit would be the most suitable for measuring the results of their experiment?
(a) hours
(b) kilograms
(c) metres
(d) Seconds

Answer : D

Question. Identify the planet that is closest to the earth.
Use the information about the Solar System given below and answer the question.

(a) Mercury
(b) Venus
(c) Mars
(d) Jupiter

Answer : B

Question. How many planets have a larger diameter than that of the earth? 
Use the information about the Solar System given below and answer the question.

(a) 2
(b) 3
(c) 4
(d) 5

Answer : C

Question. Devpal rides a bicycle for 15 minutes and then stops. The graph below shows how his pulse changes as he cycles. After he stops cycling, how many minutes does it take his pulse rate to come back to normal?

(a) 5 minutes
(b) 10 minutes
(c) 15 minutes
(d) 20 minutes

Answer : A

Question. Which of the following tables best represents the information given in the graph?
Saroja and Ali dropped the same tennis ball from a height of 1 metre on various surfaces and measured how high it bounced each time. Study the graph they made and answer the question.

Answer : C

Question. Which of these can be concluded from the information IN THIS GRAPH?
Saroja and Ali dropped the same tennis ball from a height of 1 meter on various surfaces and measured how high it bounced each time. Study the graph they made and answer the question.

(a) the bounce depends on the height from which the ball is dropped.
(b) the bounce is likely to be different for different surfaces.
(c) the bounce depends on the type of ball that is dropped.
(d) the bounce does not depend on the type of ball that is dropped.

Answer : C

Question. Ball P was moving in the direction shown. After some time it collided with ball Q. The position and direction of motion of ball P after some time is shown below. Which of these could have been the direction of motion of ball Q before the collision? 

Answer : C

Question. Here are images of three objects. The ruler shown in each image IS THE SAME. Which object is the longest?

(a) the book
(b) the eraser
(c) the mobile
(d) all are of the same length

Answer : A

Question. A rod can turn around the pin at its centre. Two strings are hooked to the rod. Mitul and Kirti pull on the strings with equal force in the directions shown. In which case will they make the rod turn?

Answer : B

Question. There are two beakers containing oil and water as shown below. Oil floats on water and does not mix with it.
If all the water from the first beaker is poured into the beaker of oil, what will be the level in the second beaker?

Answer : B

Question. The graph shows Ashok's heartbeat during the period 10:02 a.m. to 10:20 a.m. How did his heartbeat change between10:10 and 10:16?

(a) It increased and then decreased.
(b) It increased at a uniform pace.
(c) It decreased at a uniform pace.
(d) It stayed constant.

Answer : C

Question. If the earth was to rotate at twice its present rate of rotation, which of these changes is likely to be observed?
(a) There will be 2 days and 2 nights within 24 hours.
(b) There will be only 1 day OR 1 night in 24 hours.
(c) The 24 hour duration of the day-night cycle will not change.
(d) The duration of each day will be 18 hours and night 6 hours.

Answer : A

Question. What would be the season in New Delhi when the position of the earth is at R as shown in the figure? 

(a) Summer
(b) Winter
(c) Rainy Season
(d) Spring

Answer : B

Question. A measuring cylinder can be used to measure the volume of a stone. This can be done in the six steps given below. These are not put in the correct order.
1.Lower the stone with the help of a thread slowly into the cylinder.
2.Calculate the difference in the two readings.
3.Read the scale.
4.Fill the cylinder with water to the required level.
5.Take the new reading.
6.Make sure the stone is fully submerged and water does not overflow.
What is the correct order of these steps to measure the volume of the stone?
(a) 4, 3, 1, 6, 5, 2
(b) 1, 6, 3, 4, 2, 5
(c) 5, 1, 2, 4, 3, 6
(d) 3, 4, 5, 2, 1, 6

Answer : A

Question. If 10,00,00I0 &mu;g is 1 gram, about how many MILLIGRAMS of SPM would there be in 1m³ of air in Colaba in Mumbai
Study this table containing pollution data about various Indian cities on a particular day and answer the question.

(a) 0.291
(b) 2.91
(c) 291
(d) 2910

Answer : A

Question. During which of these periods did the fish production fall the most?
Observe the graph below which shows the number of tons fish caught from a lake in Canada from 1945 to 2000. The question is based on it.

(a) 1970 -1971
(b) 1977 -1978
(c) 1994 -1995
(d) 1959 - 1960

Answer : C

Question. From the given graph, what can be concluded about the commercial fish production between the years 1990 and 2000?
Observe the graph below which shows the number of tons fish caught from a lake in Canada from 1945 to 2000. The question is based on it. 

(a) It was the best decade in commercial fish production in over 30 years.
(b) Due to environmental and legal problems, fish production fell drastically.
(c) Except for a surge during the middle of the decade, it was a bad decade.
(d) The number of fish caught decreased every year during the decade.

Answer : C

Question. Consider the four tables shown here. The table top is heavy, and identical in all four cases. The legs" are made of a strong but light material and their weight can be ignored. Which table would be the most stable?"

 

Answer : D

Question. Observe the picture. The quantity being measured may be expressed in which of these units?

(a) newton per square meter
(b) kilogram per square meter
(c) kelvin
(d) Ampere

Answer : A

Question. A scientist conducts 2 laboratory investigations to determine the effect of temperature on the heartbeat rate of Daphnia (water fleas) and enters the data in a table. Which of these is a valid conclusion we can make from the data?

(a) The increase in the heart rate of Daphnia is quite uniform as the  temperature increases.
(b) The heart rate of Daphnia will be more than 500 beats per minute when the temperature is 60 degree Celsius.
(c) The heart rate of Daphnia increases initially but decreases subsequently as temperature increases.
(d) The heart rate of Daphnia almost doubles for every 10 degree Celsius  increase in  temperature.

Answer : B

Question. In this line graph, what is the relationship between the x and y variables?

(a) y increases as x increases
(b) y decreases as x increases
(c) y decreases as x increases
(d) (it is not possible to tell from the graph)

Answer : C

Question. Two identical cylindrical water bottles P and Q are taken and bottle Q is partly filled with water as shown. They are then rolled down from the top of a smooth ramp, after which is a long flat path. Which bottle will reach the finishing line first?

(a) Bottle P
(b) Bottle Q
(c) Both will reach at the same time.
(d) It is not possible to tell.

Answer : A

Question. In which of these cases will the larger wheel turn at exactly half the speed of the smaller one?

Answer : B

Question. The given map shows different possible routes from Ramesh’s house to the Railway Station. The length of each road is given. Due to traffic the average speed on roads P, Q, R and S is 15 km/h; on T is 30 km/h and on M and N is 45 km/h. Which route should Ramesh take to reach the station in the minimum possible time?

(a) M, T, Q, R, S
(b) P, Q, R, S
(c) P, T, N
(d) M, N

Answer : D

Question. The density of water is 1g/cc. Mercury is denser and kerosene is less dense than water. None of the liquids mix with each other. What will a jar that has 20 ml of water, 10 ml of mercury and 30 ml of kerosene look like?

Answer : A

Question. Raghav said that his uncle had presented him a bicycle with gears. On hearing that, his friends made these comments:
Shilpa : Impossible! Cycles can't have gears"
Sarika : "Cycles can have gears, but they are only for show."
Ali : "Cycle gears can make cycling easier, like when climbing slopes."
Jagrut : "Cycle gears can be used to help the cycle reverse."
Only one of them is correct. Who?"
(a) Shilpa
(b) Sarika
(c) Ali
(d) Jagrut

Answer : C

Question. Which of these pulse rates does NOT correctly correspond to the activity shown?

	Activity	Pulse rate (beats/min)
A	Resting	70
B	Eating	74
C	Walking	99
D	Dancing	90

(a) A
(b) B
(c) C
(d) D

Answer : C

Question. Kalpana set up the experiment shown below. She realised that when the car was released from the top of the plank, it travels a certain distance. She wanted to increase the distance that the car travelled after coming down the plank. 
Which among the following would enable her to achieve her goal?

(a) Increase the number of bricks being used.
(b) Decrease the number of bricks being used.
(c) Use a slightly longer slanted plank.
(d) Use a slightly shorter slanted plank.

Answer : A

Question. Which of the positions shown represents WINTER in Sydney, Australia?

(a) A
(b) B
(c) C
(d) D

Answer : B

Question. The lunar cycle (from one new moon to the next) is completed in about a month because in that time________
(a) the earth rotates once on its axis
(b) the earth revolves once around the sun
(c) the earth completes half a revolution
(d) the moon revolves once around the earth

Answer : D