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Lessons
- Chapter 1 – Nutrients 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 Cyclone
- Chapter 9 – Soil
- Chapter 10 – Respiration in Organisms
- Chapter 11 – Transportation in Animals and Plants
- Chapter 12 – Reproduction in Plants
- Chapter 13 – Motion and Time
- Chapter 14 – Electric Current and its Effects
- Chapter 15 – Light
- Chapter 16 – Water: A Precious Resource
- Chapter 17 – Forests: Our Lifeline
- Chapter 18 – Waste water Story
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Question Bank
- Question Bank – Chapter 1 – Nutrients in Plants
- Question Bank – Chapter 2 – Nutrition in Animals
- Question Bank – Chapter 3 – Fibre to Fabric
- Question Bank – Chapter 4 – Heat
- Question Bank – Chapter 5 – Acids, Bases and Salts
- Question Bank – Chapter 6 – Physical & Chemical Changes
- Question Bank – Chapter 7 – Weather, Climate & Adaptations of Animals to Climate
- Question Bank – Chapter 8 – Winds, Storms and Cyclones
- Question Bank – Chapter 9 – Soil
- Question Bank – Chapter 10 – Respiration in Organisms
- Question Bank – Chapter 11 – Transportation in Animals and Plants
- Question Bank – Chapter 12 – Reproduction in Plants
- Question Bank – Chapter 13 – Motion and Time
- Question Bank – Chapter 14 – Electric Current & Its Effects
- Question Bank – Chapter 15 – Light
- Question Bank – Chapter 16 – Water: A Precious Resoure
- Question Bank – Chatper 17 – Forest: Our Life Line
- Question Bank – Chapter 18 – Waste Water Story
Question Bank – Chapter 13 – Motion and Time
Chapter 13
Motion and Time
Q1. What is speed?
Ans. The distance moved by an object in a unit time is called its speed. The most convenient way to find out which of the two or more objects is moving faster is to compare the distances moved by them in a unit time. Thus, if we know the distance covered by two buses in one hour, we can tell which one is slower. We call the distance covered by an object in a unit time as the speed of the object
Q2. What are the types of motion , Explain with examples?
Ans. Straight line circular or periodic oscillary are the types of motion. Running and car moving on a straight road are the example of straight motion, merry-go-round is circular motion and a see-saw, hammer of an electric bell are oscillary motion.
Q3. State the difference between non-uniform and uniform motion.
Ans. In everyday life we seldom find objects moving with a constant speed over long distances or for long durations of time. If the speed of an object moving along a straight line keeps changing, its motion is said to be non-uniform on the other hand, an object moving along a straight line with a constant speed is said to be in uniform motion. In this case, the average speed is the same as the actual speed.
Q4. What is the basic unit and formula to get speed?
Ans. The speed of an object is the distance traveled divided by the time taken to cover that distance, Speed= total distance/ total time Its basic unit is metre per second (m/s).
Q 5. What events have been used to measure time?
Ans. Periodic events are used for the measurement of time. Periodic motion of a pendulum has been used to make clocks and watches.
Q6. What instruments are used to measure speed?
Ans. A speedometer records the speed directly in km/h. There is also another meter that measures the distance moved by the vehicle, is known as odometer
Q7. Is motion presentable in pictures?
Ans. Yes, Motion of objects can be presented in pictorial form by their distance-time graphs.
Q8. What is the use of Distance-time graphs?
Ans. Distance Time graphs provide a variety of information about the motion when compared to the data presented by a table
Q9. Which is the common smallest unit of time?
Ans. The smallest time interval that can be measured with commonly available clocks and watches is one second.
Q10 Is it possible to measure the interval between second?
Ans. Stopwatches and Quartz clocks can measure time intervals as small as one millionth or even one billionth of a second.