- #1

RetailPleb

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I am interested in knowing more about energy and performing work. In particular, if I have an object I would like to lift, how much energy I need to expend to do that.

Take for example a block of wood which has a mass of 1 kilogram, and I'd like to pick it up off the ground, say, to a height of 2 meters. If I did my homework well enough, then my understanding is that this would require the same amount of energy whether I lifted it up over a period of 1 second or 1 minute, yes?

Work = Force * Distance. Work is expressed in joules, force in Newtons, and distance in meters.

So solving for work, and knowing the distance is 2 meters, that leaves force to work out.

A kilogram mass exerts a force of about 9.8 Newtons, since the Newton is equal to 1 kg⋅1 m/s2, and on Earth that would be about 9.8 m/s2.

So work = 9.8 * 2, or approximately 20 joules of energy, is this right? 20 joules is just under 5 calories. So the amount of energy I'd need to expend to lift this is, dare I say, nearly negligible, but still measurable.

If I could trouble the community to reassure me that I'm on the right track to working this out, or correct me if I've made a mistake somewhere in here, I'd be very grateful!