An object of mass 40 kg is raised to a height of 5 m 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.
What is the work done by the force of gravity on a gatall
Answers
Answer:
Explanation:
Given:
Mass (m) = 40 kg
Acceleration due to gravity (g)= 10m/s²
Height (h)= 5m
Potential energy= m × g× h
P.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.
Answer:
Potential energy = 1960J
Explanation:
P.E. = mgh
= 40×9.8×5
= 1960J