Basic Question to settle an arguement 3

[Veeresh2006]

Take a hydraulic press. If it takes a force of 1000kN to fully compress 1 object. What force is required to fully compress 2 objects if stacked in series (one on top of the other)?
Would be pleased to have your responses.

 

[israelkk]

The same force. The two objects serve as two "springs" in series. Both objects "see" the same force. Therefore, each will be compressed by the same amount. The total compression will be doubled (the addition on the compression of each item under the 1000kN).

 

[daviedalton]

As with israelkk, the required force is the same....You still need double the energy/work, as your travel has doubled.....

 

[Barry1961]

I think the point daviedaulton made is the key to understanding this. The force remains the same but the power doubles.

If two equal springs a stacked in series you can not compress one without compressing the other. The force is the same, the stroke doubles and power doubles.

If the two springs are in parallel the force doubles, the stroke is the same and power doubles.

The power is the same with the springs in series or parallel.

Barry1961

 

[MintJulep]

Force same.

Work Double.

Power indeterminate from the information provided.

 

[Barry1961]

Good catch MintJulep!

Can not know the power without knowing the time.

Thanks
Barry1961

 

[zeusfaber]

Related scenario which might help one party or the other visualise the situation (though I have met adults who imagine a different outcome from the one I do).

Picture this:

Take an egg. Place it on a concrete floor and stand on it. Wipe your foot clean.

Take a brick. Place it on the concrete floor and stand on it. When satisfied that everything that is going to happen has finished happening, remove your foot.

Now take a new egg. Place it on the concrete floor and gently balance the brick on top of it. Now stand on the brick. Will the brick protect the egg from your bodyweight?

Sometimes, changing the question to make any variables that don't need to be the same become very different makes it easier to picture what's going on.

A.

 

[Steelforbrains]

So, did you win the argument?