Students can use Class 7 Science Curiosity Extra Questions and Chapter 8 Measurement of Time and Motion Extra Question Answer to prepare effectively at home.
Class 7 Science Chapter 8 Measurement of Time and Motion Extra Questions
Class 7 Science Chapter 8 Extra Questions on Measurement of Time and Motion
Measurement of Time and Motion Class 7 Very Short Question Answer
Question 1.
What is formula for speed ?
Answer:
Speed = \(\frac{Distance}{Time}\)
Question 2.
Name the physical quantity that helps to identify which object moves faster or slower.
Answer:
Speed
Question 3.
What is speed?
Answer:
The distance covered by an object in a unit time is called its speed.
Question 4.
How did our ancestors find out the time of the day?
Answer:
Our ancestors could tell the approximate time of the day by observing at shadows.
Question 5.
What do you mean when you say that a car is moving with a speed of 50 kilometres per hour?
Answer:
It means that the car will cover 50 kilometres distance in one hour.
Question 6.
What are the most common devices used to measure time?
Answer:
Clocks or watches are the most commonly used time-measuring devices.
Question 7.
Give an example of periodic motion.
Answer:
A well-known example of periodic motion is the motion of a simple pendulum.
Question 8.
What is a bob?
Answer:
The metallic ball in simple pendulum is called bob.
Question 9.
What is the time period of a simple pendulum?
Answer:
The time taken by the pendulum to complete one oscillation is called its time period.
Question 10.
Name the devices used by our ancestors to measure the time before pendulum clocks.
Answer:
Sundials, water clocks, hourglass and candle clocks.
Question 11.
What is speedometer?
Answer:
The device which is used to record the speed directly in km/h in the vehicles is called speedometer.
Question 12.
What is simple pendulum?
Answer:
The simple device consists of a small metallic ball and a long thread is called simple pendulum.
Question 13.
What is the function of an odometer?
Answer:
Odometer is used to measure the distance travelled by the vehicle.
Question 14.
What is the common property of most of the clocks?
Answer:
Most clocks make use of some form of periodic motion.
Question 15.
What is the basic unit of time?
Answer:
Second
Measurement of Time and Motion Class 7 Short Question Answer
Question 1.
How was time measured when there were no clocks?
Answer:
Time was measured by sundials, water clocks and candle clocks in olden times.
Question 2.
Write two types of water clocks.
Answer:
(a) Water flowing out type.
(b) Floating bowl type.
Question 3.
Shadow based measurement of time was in which reference?
Answer:
It is written in Arthashastra by Kautilya.
Question 4.
Water clock was described in which book?
Answer:
In Sardulakarnavadana.
Question 5.
Which clocks were not accurate in ancient times?
Answer:
Water clocks etc.
Question 6.
State pendular motion.
Answer:
This periodic repeating its way after a fixed interval of time then.
Question 7.
A 24 hour long days has how much ghatis?
Answer:
60 equal ghatis.
Question 8.
Name some common clocks and watches.
Answer:
Quartz clock, writst watch, stop watch etc.
Question 9.
In a race, how can we tell, who is slow or fast?
Answer:
By measuring time by comparing races of different distances too.
Question 10.
State two kinds of motion in cities.
Answer:
(a) Uniform Linear Motion, and
(b) Non-uniform Linear Motion.
Question 11.
What are the factors on which the time period of a pendulum depends?
Answer:
The time period of a simple pendulum does not depend on the mass of the bob and nature of the material of the bob. It depends upon the length of the pendulum and acceleration due to gravity.
Question 12.
Convert 36 km/h into m/s.
Answer:
To convert 36 km/h into m/s;
Multiply by \(\frac{5}{18}\)
1 km = 1000 m and 1 hour = 3600 s
1 km / 1 hour = \(\frac{3600}{1000}\) = \(\frac{5}{18}\) km / h
36 km / h = 36 × \(\frac{5}{18}\) m / s = 10 m / s
Question 13.
What do you mean by average speed?
Answer:
The total distance covered by an object divided by the total time taken is called average speed. Average speed = Total distance covered/Total time taken
Question 14.
What is an oscillation?
Answer:
An oscillation is the movement of a pendulum from its one extreme position to the other extreme position and then back to the former position.
Question 15.
Show relationship between time, speed and distance. (Imp.)
Answer:
Speed is equal to distance covered divided by total time taken.
Speed = \(\frac{Distance covered}{Time taken}\)
We can also show it by formula:
Total distance covered = Speed × time
So,
Total time taken = \(\frac{Distance covered (in total)}{Speed}\)
Question 16.
What is Average Speed ? Explain in brief.
Answer:
Speed of an object = Total distance covered divided by total time taken too. An object may not have travelled at same speed during whole time or entire duration of time at all.
An object can move slower at sometimes. Hence we calculate average speed of an object. Therefore speed is in use in inspite of average speed also.
Question 17.
Why do we use average speeds in daily life a shown by train X and Y. Show it by table.
Answer:
Data compared of train X and Y
Table: The Distances Travelled by Two Trains in Equal time Intervals of ten minutes.
(i) An object → moves along straight line with constant speed Uniform Linear Motion.
(ii) An object → moves along straight line → speed changing → Non-uniform Linear Motion train Y.
Above data shown train X, Y showing two types of motions – train X, Y show these two.
Question 18.
Distinguish between Sundial and Water clocks.
Answer:
Difference between Sundial and Water clocks
| Sundial | Water clocks |
| 1. Measurement of the time by changing position of shadow of one object. | 1. Water flow was used to measure time in/out of a vessel. |
| 2. Cast by light of sun on a day time. | 2. On vessel, these are markings for time to measure a all. |
Question 19.
State what do you know about Ghatika yantra.
Answer:
(a) This came to notice by Aryabhatta.
(b) Mentioned by astronomical text later on also.
(c) Time is measured constantly by it at royal palaces.
(d) Each time bowl sank, drum was beaten or a gong was struck too.
Question 20.
Explain how Galileo contributed to the development of clocks.
Answer:
Once Galileo was sitting in a church. He noticed that a lamp suspended from the ceiling with chain was moving slowly from one side to other. He was surprised to find that his pulse beat the same number of times during the interval in which the lamp completed one oscillation. He found that a pendulum of a given length takes always the same time to complete one oscillation. This observation led to the development of pendulum clocks and other watches.
Measurement of Time and Motion Class 7 Long Question Answer
Question 1.
State how was time measured in olden days.
Answer:
People took help of natural events to measure time. These event happen at regular intervals of time. e.g., time interval between sun rise and sun set was called a day. Again time interval from one sun set to next sun rise was one night. Time interval between one new moon to next one was terned as one month time. Time taken to more earth one resolution of sun was a year too. Moreover, one second is time measured by available clocks/watches.
Question 2.
Explain the term “speed” in brief.
Answer:
Speed refers to time interval cover a maximum distance at all e.g., we cover 100 m in 5 minutes. S.I. unit of speed is meter per second. Hence the speed in distance covered by an object or body that is moving in a unit time. Cars, trains, aeroplanes move fast than bus, scooters etc.
When an object covers a distance (d) in time (t), it speed would be as
Speed = \(\frac{Distance (d)}{Time (t) taken}\)
Speed is actually an average speed of an object at all.
Question 3.
What do you know about clocks and watches ? Explain shortly.
Answer:
The electronic wrist watches and clocks are available in markets. They have crystals of quartz, a substance. The crystals vibrate fast too and also at accurate rate. These vibration are used to measure time. A quartz clock is more accurate in comparison to a pendulum clock at all. Stop clock and stop watches are mostly used in labs of schools and sports to measure time interval. They refer to improved form of wrist watches to measure time upto one tenth of a second (s).
Question 4.
Explain slow and fast motion.
Answer:
Observe the moving and rest position of an object. Suppose you sit near a window of a moving bus/train and are looking to outside. You see that the trees appear moving fast backwards. On the centuary, a man standing on road side, sees trees to appear stationary or fixed too. So we can conclude that motion is relative, everything in our universe is in motion too. So movement of an object or a body is fast or slow. We may move faster or slower at other way. The vehicles/trains move faster or slower too. Vehicles move on a road, you can see some are faster than others (slower).
Measurement of Time and Motion Class 7 Case Based Questions
1. Read the following passage carefully and answer the questions that follow:
A simple pendulum is made up of three parts as bob, string and rigid support. During rest position, it lies in mean position. If you move bob of a pendulum it begins the oscillatory motion then. The periodic motion repeats its path when fixed time interval is observed.
(i) What makes pendulum?
(a) A string
(b) A bob
(c) A rigid support
(d) All of these
Answer:
(d) All of these
(ii) When does oscillary motion start ?
(a) Move bob
(b) Move string
(c) Move support
(d) All of these
Answer:
(d) All of these
(iii) Mention features of a pendulum.
Answer:
(a) It has a bob.
(b) It possesses a swing.
(c) It also has a rigid support.
(iv) Define periodic motion of a pendulum.
Answer:
The repeat way/path in a fix interval of time of pendulum is called periodic motion..
2. Read the following passage carefully and answer the questions that follow:
During sports day, Raju ran 100 metres in 20 seconds while Priya completed the same in 25 seconds. Their teacher used this to explain the concept of speed, calculated as distance divided by time. Later, students plotted their performances on a graph and found that while Raju ran at a constant speed, Priya ran slower at the beginning and faster toward the end.
(i) What is the formula for speed?
(a) Speed = Distance × Time
(b) Speed = Time + Distance
(c) Speed = Distance ÷ Time
(d) Speed = Acceleration × Distance
Answer:
(c) Speed = Distance ÷ Time
(ii) If Raju runs 100 m in 20 seconds, what is his speed?
(a) 5 m/s
(b) 0.2 m/s
(c) 20 m / s
(d) 2 m / s
Answer:
(a) 5 m/s
(iii) A graph showing equal distances covered in equal intervals indicates:
(a) Irregular motion
(b) Increasing speed
(c) Uniform motion
(d) Decreasing time
Answer:
(c) Uniform motion
(iv) Which of the following indicates non- uniform motion?
(a) Steady speed
(b) Oscillation
(c) Unequal distances in equal time intervals
(d) Constant velocity
Answer:
(c) Unequal distances in equal time intervals
Measurement of Time and Motion Class 7 Picture Based Questions
1. Look at the picture and answer the following questions:
(i) Identify pictures (a), (b), and (c):
(a) The boys run in a race in straight track
(b) Quartz clock
(c) Sundial
(d) All of these
Answer:
(d) All of these
(ii) What is the smallest interval of time?
(a) Hour
(b) Minute
(c) Second
(d) All of these
Answer:
(c) Second
(iii) name the device you can see in Fig (b).
(a) Hourglass
(b) Water clock
(c) Candle clock
(d) Sundial
Answer:
(d) Sundial
2. Look at the picture and answer the following questions:
(i) What does the above figure show?
(a) A simple pendulum
(b) A watch bob
(c) Oscillation
(d) None of these
Answer:
(a) A simple pendulum
(ii) What is the metalic ball called in pendulum?
(a) Circle
(b) Ball
(c) Metal ball
(d) Bob
Answer:
(d) Bob
(iii) What type of motion the bob is doing?
(a) Uniform motion
(b) Non-uniform motion
(c) Linear motion
(d) None of these
Answer:
(b) Non-uniform motion
(iv) What is the time period of a simple pendulum?
Answer:
The time taken by the pendulum to complete one oscillation is called its time period.
Measurement of Time and Motion Extra Questions for Practice
Multiple Choice Questions (MCQs)
Question 1.
In olden times, the time was measured by:
(a) sundial
(b) water clocks
(c) hourglasses
(d) All of these
Question 2.
A simple pendulum has:
(a) one part
(b) two parts
(c) three parts
(d) four parts
Question 3.
S.I. Unit of Time is:
(a) m/s
(b) cm/s
(c) None of these
(d) Both (a) – (b)
Question 4.
Motion of trains between two stations is:
(a) Linear motion
(b) Oscillary motion
(c) Non-linear motion
(d) All of these
Question 5.
Find the speed shown below as correct:
(a) Speed = Time × Distance
(b) Speed = \(\frac{Distance}{Time}\)
(c) Speed = \(\frac{Time}{Distance}\)
(d) Speed = \(\frac{1}{\text { Distance × Time }}\)
Very Short Answer Type Questions:
Question 1.
Name three parts of a pendulum.
Question 2.
What is speed?
Question 3.
What do you mean by a clock?
Question 4.
Give one limitation of sundial.
Question 5.
What is meant by time period of a pendulum.
Question 6.
State one example of a body having uniform and periodic motion.
Question 7.
How was time measured in an hourglass?
Short Answer Type Questions:
Question 1.
What are slow and fast motions?
Question 2.
Write one use of stop watch.
Question 3.
When is an object said to be in non-linear motion?
Question 4.
On what principle modern electronic watches are based?
Question 5.
Give S.I. units of speed and time.
Question 6.
Give uses of:
(a) Odometer
(b) Pendulum and
(c) Speedometer
Question 7
Write any two points of difference in uniform and non-uniform motions.
Question 8.
State the relationship between speed, distance and time.
Question 9.
Briefly explain:
(a) Sundial
(b) Water clock
(c) Candle clock
Question 10.
By a diagrammatic figure show a simple pendulum.
Long Answer Type Questions:
Question 1.
Compare uniform and non-uniform speeds. Give two examples of each.
Question 2.
How was time measured in ancient times? Write briefly.
Question 3.
On what principle do modern watches work? Explain in short.
Question 4.
Define speed. How is speed measured?
Question 5.
Draw figures of watches and clocks used at home.