The discussion centers on the concept of potential energy in the context of lifting a block with constant velocity. Participants clarify that while the net work done on the block is zero due to balanced forces, the block still possesses potential energy due to its height. This potential energy is defined as the work done against gravity to elevate the block, which can be converted into kinetic energy when the block is released. The work-energy theorem is emphasized, indicating that energy is conserved even when the net work is zero.
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It should gain some energy, as when we will release the block, the block will gain kinetic energy, indicating it must have had some form of energy at the height which is converted into kinetic energy.FactChecker said:Why do you think that it should gain potential energy?
The work done by all forces is zero, that means the KE does not change (work-energy theorem).Vatsal Goyal said:Homework Statement
If we lift a block with constant velocity, by applying a force mg upwards, is the work done zero?
How is the potential energy of a body at a point due to a force defined?Vatsal Goyal said:Homework Equations
The Attempt at a Solution
The work done must be zero as the resultant force is zero, what I don't understand is how does the block get potential energy if no work is being done?
The block has some potential energy initially due to the height that it starts at.. Do you think that the force increases it? If so, why?Vatsal Goyal said:It should gain some energy, as when we will release the block, the block will gain kinetic energy, indicating it must have had some form of energy at the height which is converted into kinetic energy.
It is defined as the energy a body has due to its position or configuration, and measured by the work that could be done by a body passing from its present position to some zero position.ehild said:How is the potential energy of a body at a point due to a force defined?
Yes, I think it would, suppose the block is at height h in the beginning. We lift it by a distance x with velocity u. Now, if we drop it, when it reaches height h, it will have velocity v>u as only force of gravity is acting on it, hence total energy at h is greater than what it was before, then at height h+x, it must have had some extra energy, which is giving the extra kinetic energy at h.FactChecker said:The block has some potential energy initially due to the height that it starts at.. Do you think that the force increases it? If so, why?
Potential energy due to a conservative force is defined as the work done by that force when the body passing from its present position to the position of zero potential energy.Vatsal Goyal said:It is defined as the energy a body has due to its position or configuration, and measured by the work that could be done by a body passing from its present position to some zero position.
Yes. The first step is to calculate the values of x and u. They may be positive, negative, or zero.Vatsal Goyal said:Yes, I think it would, suppose the block is at height h in the beginning. We lift it by a distance x with velocity u. Now, if we drop it, when it reaches height h, it will have velocity v>u as only force of gravity is acting on it, hence total energy at h is greater than what it was before, then at height h+x, it must have had some extra energy, which is giving the extra kinetic energy at h.
Vatsal Goyal said:Homework Statement
If we lift a block with constant velocity, by applying a force mg upwards, is the work done zero?Homework Equations
The Attempt at a Solution
The work done must be zero as the resultant force is zero, what I don't understand is how does the block get potential energy if no work is being done?