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