work (1 Viewer)

[dawso]

'explain that a change in gravitational potential energy is related to work done"

anyone giv me a quick summary of what is meant by this dot point and remind me waht exactly 'work' is...

thanx in advance

-dawso

 

[wanton-wonton]

'explain that a change in gravitational potential energy is related to work done"

anyone giv me a quick summary of what is meant by this dot point and remind me waht exactly 'work' is...

thanx in advance

-dawso

This is a very simple one. Here's what I wrote:

ΔE_P = work done to move to the point
= force required x distance moved
= mg × h
= mgh

 

[dawso]

so basically work is just the force x the time that the force is needed 4?
i still dont get work....

 

[zeropoint]

so basically work is just the force x the time that the force is needed 4?
i still dont get work....

The force multiplied by the time over which the force acts is the impulse which equals the change in momentum of the object. The work done by a force is equal to the force multiplied by the distance over which the force is applied. The work done by the gravitational force, is W = F s = mg (y1 - y2) = -ΔEp.

 

[zenger69]

you can also use the -gm1m2/r.

As Work = Force x distance

Force = gm1m2/d^2

and when multiplied by distance .... u get gm1m2/d. And it's minus because it's falling towards the earth.

So yeh Gravitational Potential Energy.

I used the F=mgh in a test and the teacher said that formula was too basic.

 

[Jaydels]

I used the F=mgh in a test and the teacher said that formula was too basic.

How can a formula be too basic? Did it give you the right answer?

 

[FinalFantasy]

How can a formula be too basic? Did it give you the right answer?

it's "too basic" cuz da formula E=mgh is only supposed to use when taking 'ground' as zero potential energy lvl, but on da larger scale it's not like dat and wouldn't work properly.

 

[Jaydels]

it's "too basic" cuz da formula E=mgh is only supposed to use when taking 'ground' as zero potential energy lvl, but on da larger scale it's not like dat and wouldn't work properly.

oh i see what you mean now

 

[zenger69]

I dunno what would happen if I wrote the mgh in the HSC.

Would I get penalised.......... Becuase the mgh is so much easier to explain.

 

[Xayma]

You can be penalised. Unless it says to take it's potential energy at ground level to be 0 (in which case you would have to derive). It isn't a formula in the formula sheet hence I would be very wary of using it.

 

[Jaydels]

I dunno what would happen if I wrote the mgh in the HSC.

Would I get penalised.......... Becuase the mgh is so much easier to explain.

It only works when the gravitational field is uniform, I don't think they ask many questions like that