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Apply the formula of power $P\ \mathrm{(W)}$ required for lifting the mass $m\ \mathrm{(kg)}$ with a constant velocity $v\ \mathrm{(m/s)}$ $$\text{power}=\text{(force)}\times (\text{velocity})$$ $$P=mgv$$ remember the starting torque shouldn't exceed the maximum torque of engine or it can't lift the weight.

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The pressure at the bottom of the water tank is large. You have to push the balls in against this pressure - that is exactly as much work as you will get back. No free lunch in nature. Sorry.

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You're right that the unit "megawatt" is abbreviated MW. However, as Aniket comments, watt itself means "energy per unit time", so saying that the power plant produces 60 MW per hour doesn't make sense. In your comment, you question whether MW is a "basic unit". I'm not exactly sure what you mean by this, but the SI unit of power is watt, so if you want to ...

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$\mathrm{Watt}$ (or Joule per second or $\mathrm{J/s}$) is the SI unit of power. So megawatt is a valid unit of power (expressing power with order of magnitude $10^6$) and is used mainly in commercial statements. Definition: Power means the quantity of energy consumed or produced per unit time. So $\mathrm{MW/hr}$ actually makes no sense since it ...

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Notice, the unit of power is $~\mathrm{J/s}$ or $~\mathrm{W(Watt)}$. The unit $~\mathrm{MW}$ indicates the energy (in $~\mathrm{mega\ joules}$) produced by power-plant per unit time (in $~\mathrm{seconds}$) The unit $~\mathrm{60 \ MW\ per \ hour}$ doesn't represent a physical quantity.

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when people refer to a "powerful" car ... they actually mean acceleration. This means Torque (which gets translated to Force at the end of the drivetrain). And Force = m x a ... so for a given mass, Torque == Force == acceleration. Unfortunately, the technical definition of the term Power is defined as Torque x Revs. This means the Power curve is sort of ...

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1.) You lose energy by doing work. The difintion of work by itself is the product of force and dislplacement(if the force is onstant) or else $\int_{}{}F dx$ for non constant forces.In case the case of doing a plank, you do zero work though you are resisting the force of gravity. So in terms of physics, you lose 0 energy even though you get tired. The reason ...

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At huge scale, there is another way to get energy from gravity: letting a huge mass of gaz/dust/rocks collapsing by self-gravity into a star or a planet. This cause huge heating, sometime light, and for star, nuclear reactions, all that can be used for work.

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Hydraulic barrages and all water turbines are exactly doing that (getting either electricity or mechanic power). In practice Earth gravity induces the notion of potential energy related to the altitude of a mass. By lowering the altitude, you can convert potential energy in kinetics energy or others.

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This is actually quite simple. You measure the maximum no-load velocity of the Turbine and divide it with 2. At this speed you have the highest power. Practically the optimal value is between 1.8-2.3, depending on turbine type. This all is clearly explained in the book of Carl Pfleiderer, Strömungsmachinen, 1952. Page 248. The diagramm has the rpm on ...

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This is a bizarre question. Newton's laws do include internal forces. However, Newton's third law happens to cancel out their overall effect on a center of mass. But, if you want to understand the motions of the constituent parts of the system, then you do have to understand their internal forces. So let's assume that we have a collection of particles ...

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