- #1
Miraj Kayastha
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This question may sound weird but when we lift an object with a force equal to the weight of the object up to a certain height the Earth is doing negative work on the object as well. So shouldn't the net work be zero?
Miraj Kayastha said:What I meant was:
Consider a particle on the ground. This particle is raised by a force of magnitude mg to a height h above the ground. At this point, the work done on the particle by the force is mgh, which is equal to the potential energy of the particle. But, during this period, the force of gravity also acts on the particle and is displaced by h, and so does a work of −mgh on the particle. Shouldn't the two cancel and no net work should be done on the particle?
If they don't cancel, then where did the energy that came from the work done by the force of gravity go?
This is backwards. Positive work done by some system S decreases the energy of S. So negative work by S would increase the energy of S.Miraj Kayastha said:But what about the negative work done by the Earth on the mass when the mass is lifted? Shouldn't that decrease the energy of the earth-mass system?
DaleSpam said:This is backwards. Positive work done by some system S decreases the energy of S. So negative work by S would increase the energy of S.
Miraj Kayastha said:Here you said the system gains energy because Earth also does negative work on the mass.
Gravitational potential energy is the energy an object possesses due to its position in a gravitational field. It is calculated by multiplying the object's mass by the acceleration due to gravity (9.8 m/s²) and the object's height above the ground.
Work done is the transfer of energy from one form to another. In the case of gravitational potential energy, work is done when an object is moved against the force of gravity. The work done is equal to the change in the object's gravitational potential energy.
Yes, the gravitational potential energy of an object changes when its height changes. As an object is raised to a higher height, its potential energy increases, and as it is lowered to a lower height, its potential energy decreases.
No, gravitational potential energy can be positive, negative, or zero. The sign of the potential energy depends on the reference point chosen. For example, an object at a height of 0 meters has zero potential energy, while an object at a height of -10 meters would have a negative potential energy.
Yes, the gravitational potential energy of an object can be converted into other forms of energy. When an object falls, its potential energy is converted into kinetic energy. If the object is connected to a pulley system, its potential energy can be converted into mechanical energy. In some cases, the potential energy of an object can also be converted into heat or sound energy.