Answer with Explanation:
Mass of rock=2 kg
Height of rock=29 m
Total energy of rocks is equal potential energy at height 29 m due to rest
Total energy of rock=[tex]mgh[/tex]
Where m=Mass of rock
g=[tex]9.8 ms^{-2}[/tex]=Acceleration due to gravity
h=Height of rock
Substitute the values then we get
Total energy of rock=[tex]2\times 9.8\times 29=568.4 J[/tex]
By conservation law of energy
Total energy 568.4 is equal to mechanical energy at each height.
When rock falls and loses its potential energy and this loss of potential energy convert into kinetic energy at each height.
1.h=20 m
Potential energy=[tex]2\times 20\times 9.8=392 J[/tex]
Kinetic energy=[tex]568.4-392=176.4 J[/tex]
2.h=15 m
Potential energy=[tex]2\times 15\times 9.8=294 J[/tex]
Kinetic energy=[tex]568.4-294=274.4 J[/tex]
3.h=5 m
Potential energy=[tex]2\times 5\times 9.8=98 J[/tex]
Kinetic energy=[tex]568.4-98=470.4J[/tex]
4.h=9 m
Potential energy=[tex]2\times 9\times 9.8=176.4 J[/tex]
Kinetic energy=[tex]568.4-176.4=392 J[/tex]
