**Lakhmir Singh Manjit Kaur Class 7 Science 13th Chapter Motion And Time Solutions**

Lakhmir Singh and Manjit Kaur Science solution: Motion And Time Chapter 13. Here you get easy solutions of Lakhmir Singh and Manjit Kaur Science solution Chapter 13. Here we give Chapter 13 all solution of class 7. Its help you to complete your homework.

**Board –**CBSE.**Text Book –**SCIENCE.**Class –**7.**Chapter –**13.

__Very Short Answer Type Question Solution:__

__Very Short Answer Type Question Solution:__

**(1) ****Ans:- **M/S.

**(2) ****Ans:- **Km/Hr.

**(3) ****Ans:- **Speed.

**(4) ****Ans:- **Km/Hr.

**(5) ****Ans:- **(a) Odometer.

(b) Speedometer.

**(6) ****Ans:- **(a) False

(b) False

(c) True

(d) False

(e) True

(f) True

(g) False

**(7) ****Ans:- **Bar graph, Pie chart.

**(8) ****Ans:- **Time

**(9) ****Ans:-** Second.

**(10) ****Ans:- **Hour, Minute, Second.

**(11) ****Ans:- **3600.

**(12) ****Ans:- **Sundial, Water clock.

**(13) ****Ans:- **Simple Pendulum.

**(14) ****Ans:- **Month, Day.

**(15) ****Ans:- **Bob.

**(16) ****Ans:- **Periodic Motion.

**(17) ****Ans:- **Quartz Crystal.

**(18) ****Ans:- **Clocks, Watches.

**(19) ** **Ans:- **(a) 1 Second

(b) 1/10^{th} Second.

**(20) ****Ans:-** Micro Second.

**(21) ****Ans:-** A quartz clock.

**(22) ****Ans:- **A quartz clock.

**(23) ****Ans:-** Speed = Distance covered / Time; 10m / 40 s = 0.25 m/s.

**(24) ****Ans:- **0.2 hour.

**(25) ****Ans:- **An instrument on a vehicles dashboard which indicates the speed of the vehicle when it is running is called speedometer.

**(26) ****Ans:- **An instrument which is used for measuring the distance travelled by a vehicle.

**(27) ****Ans:- **when the object is stationary.

**(28) ****Ans:- **Speed of an object is the distance travelled by it in unit time.

**(29) ****Ans:- Speed = Distance Covered / Time Taken.**

**(30) Fill in the blanks**

**Ans:- **(a) Speed

(b) no-uniform

(c) uniform

(d) straight

(e) month

(f) day

(g) periodic

(h) simple pendulum

(i) time-period

__Short Answer Type Question Solution:__

__Short Answer Type Question Solution:__

**(31) ****Ans:- **(a) Periodic

(b) Rectilinear

(c) Periodic

(d) Periodic

(e) Rectilinear motion.

**(32) ** **Ans:- **(a) A bar graph is a diagram which shows information as bars of different heights.

Example:- A bar graph showing the information about the runs scored in six overs of a cricket match.

(b) A pie chart is a kind of graph or diagram which shows the percentage composition of something in the form of slices of a circle.

Example: A pie chart showing the composition of air.

**(33) ****Ans:- **(a) Rectilinear motion.

(b) Circular motion

(c) Periodic motion

(d) Rectilinear motion

(e) Rotational motion.

**(35) ****Ans:- **The distance between Delhi and Amritsar is = Speed x Time Taken

=> 75 km/h x 6 h

=> 450 km.

**(36) ****Ans:- **Time taken = Distance Travelled / Speed

= 270 km / 60 km/hr

= 4.5 hr.

**(37) ****Ans:- **Distance Covered = 1 metre = 100 cm

Time taken = 10 second

Speed = 100 cm / 10 s = 10 cm/s

**(38) ****Ans:- **Speed = 120 km

Time taken = 1 minute

= 1 / 60 hr.

Distance Travelled = 120 x 1/ 60

= 2 km.

**(39) ****Ans:- **Speed = 45 km /h

Time taken = 20 minutes

= 20 / 60 = 1 / 3 h.

Distance Travelled = 45 x 1 / 3

= 15 km.

**(40) ****Ans:- **Total Distance = 240 km

Time taken = 4 hours

Speed = 240 km / 4 hr

= 60 km / hr.

**(41) ****Ans:- **Distance = 5 m 20 cm

= 500 + 20 = 520 cm

Time taken = 4 sec

Speed = Distance travelled / Time taken

= 520 cm / 4 sec = 130 cm/sec

**(42) ****Ans:- **Train speed = 60 km/hr

=60/60 km/min

=60/60×60 km/sec

=60×1000/60×60 m/sec

=16.66 m/sec.

**(43) ****Ans:- **Speed of the racing car=60m/s

1m =1/1000 km

1s 1/3600 h

Speed of car in km /h =(60×3600)÷1000

=216km/h

**(44) ****Ans:- **(a) Uniform motion.

(b) Non Uniform motion.

**(45) ****Ans:- **(a) Circular motion

(b) Rotational motion

(c) Periodic motion

(d) Periodic motion.

__Long Answer Type Question Solution:__

__Long Answer Type Question Solution:__

**(46) ****Ans:- Uniform Motion:- **an object moving along a straight line path is said to have uniform motion is its speed remains constant.

Example: The motion of a car running at a constant speed.

**Non Uniform Motion:- **An object moving along a straight line path is said to have non uniform motion if its speed keeps changing.

Example: The motion of a train starting from a railway station.

**(50) ** **Ans:- Simple Pendulum:- **A simple pendulum consists of a small metal ball suspended by a long thread from a rigid support such that the bob is free to swing back and forth.

Time Period of a Simple Pendulum:- The time taken by pendulum bob to make one complete oscillation is called time period of the pendulum.

(b) Time taken for 20 complete oscillations = 36 s.

Time taken for 1 oscillation = 36 s / 20 = 1.8 s

Thus, the time period of this pendulum is 1.8 seconds.

**Higher Order Thinking Skills (HOTS)**

According to the question the graph shows the relation between time and distance covered by two vehicles A and B. From the graph 2 we can see that for constant time vehicle A has moved to point P and vehicle b has moved to point Q. Now it is clear that OP is greater than OQ. So we can clearly see that vehicle A has travelled more distance than vehicle B in the same time. To sum up, we can say that vehicle A is moving faster.

**72) **

Graphs are a very important tool for representing various kinds of information. Some of the popular types of graphs that we use regularly to depict the relation between variables are line graph, bar graph, pie chart etc.Not all graphs are suitable to represent all types of information. For example the runs scored in various overs of a cricket match can be beautifully represented by bar graphs. The variation of distance covered by a car with time can be represented by a line graph. Pie chart can be quite useful while representing the composition of air.

**73)**

The distance time graph shows how the distance travelled by a moving object changes with time.

Below we have given the graphical representation of the relation between distances covered in a specific time of moving objects

a) The graphical representation of the relation between distance and time of a car that is moving with a constant speed is given below.

In this graph we can see that the distance covered in a unit time is same for the entirety of its journey. So we can say that the vehicle is moving at a constant speed.

b) The graphical representation of the relation between distance and time of a car that is parked on the side of a road is given below.

In this graph we can see that with time increasing the distance travelled by the vehicle not changing. So we can say that the vehicle is stationary or parked on the side of a road.

**c)** The graphical representation of the relation between distance and time of a car that is moving with a changing speed is given below.

In this graph we can see that the distance covered by the car for a unit time is changing so we can say that the car is moving with a changing speed.

**74)**

The time distance graph for a truck which is moving with a speed that is not constant is given below.

From this graph if we can observe that the distance covered by the truck for a unit time keeps changing for its entire journey. When the graphs are curved in a distance time graph it can be said the speed of the object is non-uniform.

**75)**

If the distance – time graph of an object is a straight line perpendicular to the distance axis then we can say that the object is not moving. From the graph we can see that the distance travelled by the object is not changing with time which proves that the object is stationary or not moving.

**Next Chapters Solution Link:**

**Chapter 1) Nutrition in Plants****Chapter 2) Nutrition in Animals****Chapter 3) Fibre to Fabric****Chapter 4) Heat****Chapter 5) Acids, Bases and Salts****Chapter 6) Physical and Chemical Changes****Chapter 7) Weather, Climate And Adaptations of Animals to Climate****Chapter 8) Winds, Storms And Cyclones****Chapter 9) Soil****Chapter 10) Respiration in Organisms****Chapter 11) Transport in Animals and Plants****Chapter 12) Reproduction in Plants****Chapter 14) Electric Currents and Its Effects****Chapter 15) Light****Chapter 16) Water: A Precious Resource****Chapter 17) Forests : Our Lifeline****Chapter 18) Wastewater Story**

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