IV. Long answer type questions
1. Why is the measurement of time important to us?
2. How did people in earlier days measure time using the following?
a. sundial b. Hourglass
3. Describe an activity to demonstrate the constancy of the time period of a pendulum.
4. What is a distance-time graph? How can we find the speed of an object from its distance-
time graph?
5. Distinguish between uniform and non-uniform motion. Also, give examples of each.
answers the following Questions
Answers
Answer:
1.Time provides us with a measure of change by putting dates on moments, fixing the durations of events, and specifying which events happen before which other events.
2.a)sundial
3.[TAKE ANY ONE POINT , THE EXTREME POSITION IN THE OSCILLATION OR THE MEAN POSITION OF THE STONE AND COUNT THE NUMBER OF TIMES THE STONE CROSSES THIS POINT , IN THE SAME DIRECTION]. STEP :4 DIVIDE THE TIME TAKEN FOR TEN OSCILLATIONS BY 10. THIS GIVES TIME PERIOD OF THE PENDULUM .
4.If an object moves along a straight line, the distance travelled can be represented by a distance-time graph. In a distance-time graph, the gradient of the line is equal to the speed of the object. The greater the gradient (and the steeper the line) the faster the object is moving.
5.Rectilinear motion has zero acceleration. Example of uniform motion: A body moving with a constant speed in a straight line has uniform motion. Non-uniform motion: When an object covers an unequal distance in equal interval of time, the motion is called non-uniform motion.
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