Class 7 Time and Motion Important Questions VBQs

Class 7 Time and Motion Important Questions VBQs. Please refer to the examination notes which you can use for preparing and revising for exams. These notes will help you to revise the concepts quickly and get good marks.

TIME AND MOTION

CHAPTER 13
 
MOTION AND TIME
 
Activity 1
 
Aim: To find the time period of a simple pendulum by changing the length of the string.
 
Materials required:

Theory:
 
Diagram :
 
Procedure :
 
Observation table:

 
Conclusion:
 
CHAPTER 13
 
MOTION AND TIME Assignment 13.1
 
Multiple Choice Questions
 
Tick the correct option(s):-
 
1) Which of these are units of time?
 
a) second

c) light year

d) year
 
2) The time period of a simple pendulum depends upon

a) length of pendulum
 
b) mass of bob

c) amplitude of oscillating pendulum

d) length of string
 
3) The distance covered by an object can be calculated by the formula

a) speed / time
 
b) time / speed

c) speed x time

d) speed + time
 
4) The instantaneous speed of a vehicle is measured by

a) odometer
 
b) ammeter

c) anemometer

d) speedometer
 
5) The graph of an object moving with uniform motion is a

a) curved line
 
b) straight line parallel to time axis

c) straight line parallel to distance axis

d) straight line inclined towards time axis
 
6) Which of the following is not a time measuring device?
 
a) sun dial

b) water clock
 
c) odometer

d) sand clock
 
7) The SI unit of speed is

a) m x s
 
b) m/s

c) km/h

d) km/min

8) The motion of a simple pendulum is

a) oscillatory
 
b) rectilinear

c) periodic

d) circular

9) The clocks and watches which have an electric circuit with one or more cells are

a) quartz clocks
 
b) pendulum clocks

c) water clocks

d) digital clocks
 
10) The SI unit of distance is

a) metre
 
b) kilometre

c) centimeter

d) odometer
 
11) Which of these is not a unit of speed?
 
a) m/s

b) km/h

c) s/m

d) km/min
 
12) The unit of time period is

a) second
 
b) metre

c) metre per second

d) (second)2
 
13) Which clock is most accurate?
 
a) sundial

b) waterclock

c) hourglass

d) pendulum clock
 
CHAPTER 13
 
MOTION AND TIME Assignment 13.2
 
Label the diagram of simple pendulum given below :-

 
Label the following parts:-
 
Clamp stand, length of pendulum, bob, extreme positions, mean position, amplitude
 
Explain the following:-
 
Bob –
 
One oscillation of pendulum -
 
Time period –
 
Frequency -
 
Answer the following questions:-
 
Name some devices to measure time which were used before pendulum clocks became popular?
 
Write the SI units of
 
(a) distance

(b) time

(c) speed
 
3. Which device measures the speed of a vehicle at an instant?
 
4. Which device measures the distance travelled by a vehicle?
 
5. What type of motion is exhibited by a simple pendulum?

6. Plot distance-time graph for the following data and interpret its motion:- 

 
CHAPTER 13
 
MOTION AND TIME Assignment 13.3
 
Identify the following devices and write them in the space provided:-

CHAPTER 13
 
MOTION AND TIME Assignment 13.4
 
Answer the questions for each of the figure:-
 
What can you say about the motion of the body in each of the graphs?

 
Calculate the speed for the given graphs :-
 
a) Calculate speed of the body between 0 – 200 s graphica

 
(b) Calculate the speed of the body between 0 – 50 s.

 
CHAPTER 13
 
MOTION AND TIME Assignment 13.5
 
Motion – An object is said to be in motion if its_______ changes with________ with respect to a stationary object.
 
Fast / Slow – An object is said to be fast if it covers a certain distance in_________ time.

An object is said to be slow if it covers the same distance in_____ time.
 
Uniform motion – An object moving along a___________  line with___________  speed (covers equal distances in equal intervals of time) is said to be in uniform motion.
 
Non-uniform motion – An object moving along a________line with___________speed (covers unequal distances in equal intervals of time) is said to be in non-uniform motion.
 
Speed – It is the_________ travelled per unit time by a moving object.
 

 
The SI unit of distance is metre (m).
 
The SI unit of time is second (s).
 
The SI unit of speed and average speed - metre per second (m/s).
 
Another unit often used is kilometer per hour (km/h).
 
Speedometer – It records the_______ of a vehicle in km/h at every instant of time when the vehicle is moving.
 
Odometer – It measures the________ travelled by a vehicle.
 
CHAPTER 13
 
MOTION AND TIME Assignment 13.6
 
Relation between speed, distance and time
 
                 Distance
 
Speed = ---------------

                   Time
 
or Time = --------------- Distance
 
                        Speed
 
or distance = speed x time
 
1. What is the speed of a car which travels 60km in 2h?
 
2. Our school bus travels 15 km at a speed of 45 km/h. How much time will it take to reach school?
 
3. The distance travelled by our car in 20 min is 9km. Calculate its speed in km/h. Convert it into m/s.
 
4. A box of chocolates is kept at a place 50 m away. How long will a boy take to reach the box if he runs at a speed of 10 m/s.
 
5. A train covers first 100 m in 2h and the next 100 m in 1h. Calculate its average speed.
 
6. The bus covers 40km in 1h and the next 50 km in 1h. What is the average speed of the bus?
 
7. A car takes 20 min to cover a distance of 15 km. Find its speed in km/h and m/s.
 
8. A man driving at an average speed of 40 km/h takes 6 h to travel from one town to another. 
What is the distance between the two towns?
 
9. The distance between two towns is 400 km. How much time would it take a car to cover this distance at an average speed of 50 km/h?
 
10. What is the time period of a simple pendulum which completes 20 oscillations in 40seconds?
 
CHAPTER 13
 
MOTION AND TIME Assignment 13.7
 
(A) Give one word for the following:-
 
• Distance travelled per unit time by an object – _____________
 
• Time taken by a simple pendulum to complete one oscillation –  _____________
 
• Motion of an object moving in a straight line with constant speed –  _____________
 
• Motion of a pendulum and hands of a clock –  _____________
 
• SI unit of speed –  _____________

• Shape of graph for an object moving with non-uniform motion –  _____________
 
• Device to measure the distance moved by a vehicle –  _____________
 
• Device which records instantaneous speed of a moving vehicle -  _____________
 
• SI unit of time –  _____________
 
• Clocks which have electric circuits with one or more cells -  _____________
 
(B) Answer the following questions:-
 
a) If you want to change the time period of a simple pendulum, what should you do?
 
b) What is meant by uniform motion and non – uniform motion? Give one example of each.

c) What are the usual units to measure distance and speed?

d) When is s body said to be in motion?
 
e) What is the SI unit of time period?
 
CHAPTER 13
 
MOTION AND TIME
 
HIGH ORDER THINKING SKILLS
 
1. How is a stop watch different from an ordinary watch?
 
2. Pendulum clocks generally run fast in winter and slow in summer. Why?
 
3. Why is ‘invar’ used in making a pendulum clock?
 
4. The bob of a simple pendulum is made of wood. If it is replaced by a similar bob made of iron, how will it change the time period of the pendulum?
 
5. out why and how the concept of TIME evolved?

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