Page 114 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key
P. 114

v     A simple pendulum contains a metallic ball, called bob, suspended from a rigid support by
                a thread.

          v     The rest position of the pendulum is called its mean position.
          v     Extreme position means the positions of the bob when it is moving to & fro about its mean

                position.
          v     The to and fro motion of the pendulum about its mean position is called oscillatory motion.
          v     1 oscillation of a simple pendulum is a complete back-and-forth movement from one side

                to the other & back again.
          v     The time taken by the pendulum bob to complete one oscillation is called its time period.

          v     The time period of a given simple pendulum remains contant. It depends only upon the
                length of the thread & the gravity.

          v     Second (s) is the SI unit of time.
          v     1 hour = 60 minutes

                1 minutes = 60 seconds.
          v     1 km = 1000 m
                1 m = 100 cm.

          v     If you have to convert km/h to m/s, then multiply by    5  .
                                                                       18

                if you have to convert m/s to km/h, then multiply by   18 .
                                                                        5

          v     A graph is a picture or a diagram that shows the relationship between two or more variable

                quantities.
          v     Pie graph is a graph in the shape of a circle in which different sectors of the circle represent

                the proportion of the component they represent against the whole quantity.

          v     A bar graph shows bars & each bar represents a component for comparison. This type of
                graph represents how one quantity changes with a change in the other quanity. It has two

                axes – x-axis & y-axis.
          v     Line graph also uses the x-axis and the y-axis. Specific data points are marked on the graph

                & are joined together by a single line.

          v     A distance-time graph is a type of line graph in which time is represented on the x-axis & the
                distance covered by the object is represented on the y-axis.

          v     The slope of a distance-time graph represents the speed of the object. More inclined the
                slope, more is the speed of the object.

          v     The famous scientist Galileo Galilei experimented with various pendulums & found that a

                pendulum of a given length always takes the same time to complete one oscillation. This
                observation led to the development of pendulum clocks.



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