an object of mass 40 kg is raised to a height of 5m above the ground ...what is its potential energy?If the object is allowed to fall ..find its kinetic energy when it is half way down.....
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Answers
Explanation:
See answer in above picture
Explanation:
Given:
Mass (m) = 40 kg
Acceleration due to gravity (g)= 10m/s²
Height (h)= 5m
Potential energy= m × g× h
Potential energy= m × g× hP.E= 40 × 10 × 5 = 2000J
Potential energy = 2000J ( 2000 joules)
At a height of 5 metre object has a potential energy of 2000 J.
When this object is allowed to fall and it is Half way down its height above the ground will be half of 5 m= 5/2= 2.5m.
P.E at Half way down= m× g×h
P.E= 40× 10 × 2.5= 1000J [h= 2.5 m]
Potential Energy at Half way down= 1000 joules.
According to law of conservation of energy:
Total potential energy= potential energy at Half way down+ kinetic energy at Half way of a down
2000 = 1000 + K.E at Half way down
K.E at Half way down= 2000- 1000= 1000J
Kinetic energy at half way down= 1000 joules.