II. Answer the following questions in short:
1. When would we say that an object is in motion?
2. What do you understand by uniform motion and non-uniform motion? Give examples.
3. Define speed. What are different units of speed?
4. What is the drawback of a sundial clock?
5. Define average speed. How can you calculate average speed?
Answers
Answer:
1-You can describe the motion of an object by its position, speed, direction, and acceleration. An object is moving if its position relative to a fixed point is changing. Even things that appear to be at rest move.
2-More examples of Uniform motion are: Movement of hands of a watch, Rotation and revolution of the earth, Movement of the blades of a ceiling fan etc. Do you know why Oil and Water does not mix together? A body is said to be in a non-uniform motion if it travels unequal distances in equal intervals of time.
3-Speed has the dimensions of distance divided by time. The SI unit of speed is the metre per second, but the most common unit of speed in everyday usage is the kilometre per hour or, in the US and the UK, miles per hour.
4-The most major drawback of sundial is that it cannot be used in the night. Further it has to be kept outside and cannot be used inside the house or it cannot be wore on a wrist.
5-The average speed of an object is the total distance traveled by the object divided by the elapsed time to cover that distance.
Explanation:
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