V
VI. Answer the following questions :
1. Define time.
2. What is the most ancient unit of time? Define it.
3. What is a pendulum? What for a pendulum is used?
4. What kind of measuring device you will use, (1) to tell time at any place, (ii) to tell time
for 100 metre race?
5. What is the SI unit of time? Name its four multiples.
6. Starting from solar day, write all the sub-multiples of time and state their magnitudes.
7. Who invented sundials in India? Name the places where these sundials are located.
8. Why do we say that rest and motion are relative terms?
9. Define variable speed. Support your answer by two examples.
Answers
Answer:
1) Time is the indefinite continued progress of existence and events that occur in an apparently irreversible succession from the past, through the present, into the future.
2) The hamuštum is approximately seven days long, but scholars disagree as to whether it was exactly seven days (like the modern "week") or an interval equal to about one-fourth of a lunar calendar month (which would make it vary between seven and eight days).
3) Pendulum, body suspended from a fixed point so that it can swing back and forth under the influence of gravity. ... Pendulums are used to regulate the movement of clocks because the interval of time for each complete oscillation, called the period, is constant.
4) usually we a use stop watch to measure the particular time. hence, to measure time of 100m race we can use a stop watch..
5) The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency Cs. , the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s–1..
There are seven base units in the SI system:
the kilogram (kg), for mass.
the second (s), for time.
the kelvin (K), for temperature.
the ampere (A), for electric current.
the mole (mol), for the amount of a substance.
the candela (cd), for luminous intensity.
the meter (m), for distance
7) Maharaja Jai Singh I .
sundial was invented by Maharaja Jai Singh I . One of the places where such sundials are located is Jaipur. there is a very huge sundial in jaipur that tells us accurate time.
8) Rest and motion are the relative terms because they depend on the observer's frame of reference. ... So if two different observers are not at rest with respect to each other, then they too get different results when they observe the motion or rest of a body.
9) Variable speed is defined when a body travels a given distance within the given interval of time, but the rate of traveling the distance differs with respect to time. For example: while driving a car or bike, the driver travels the distance but not with same speed.
Hope it helps u. (✿❛◡❛)