Explanation:
(i) Height of tree, h = 4 m
Mass of Ninja, m = 30 kg
The gravitational potential energy on the top branch of the tree is given by :

g is acceleration due to gravity

(ii) If he were at a height of 2 meters from the ground, its potential energy will be :

g is acceleration due to gravity

Therefore, this is the required explanation.
Answer:
A hydrometer is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water
About what elemental trip through europe
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