Answer
Hertzsprung-Russell (HR) diagram is an essential tool used in stellar evolution. In the universe, there are several hundreds of billions of stars. Scientists use the tool, in differentiation, the billions of stars in the world from the sun. In the HR tool, there is plotting of the luminosity or energy output of a star, which is plotted on the X-axis of a graph against the absolute magnitude. The sun's magnitude is an absolute of +48, which, when plotted against its luminosity, helps in setting an apparent variance between the sun and any other star. Additionally, the sun has been identified as the primary star with a very high temperature. Hence the tool can locate the sun from other forms of stars. HR diagrams outline data such as temperature and luminosity or energy. However, star distance from the Erath is not a type of data represented in the charts.
Explanation:
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Answer:
Part a)

Part b)
Direction = upwards
Explanation:
When ball is dropped from height h = 4.0 m
then the speed of the ball just before it will strike the ground is given as



Now ball will rebound to height h = 2.00 m
so the velocity of ball just after it will rebound is given as



Part a)
Average acceleration is given as



Part B)
As we know that ball rebounds upwards after collision while before collision it is moving downwards
So the direction of the acceleration is vertically upwards
Im not so sure but it should be the
instantaneous speed