Nother physics question

[LBD]

seeing we liked the last one so much, heres another...

You have an accurate scale and a 10L container of water. At sea level this weighs (has a mass of) 10 kg precisely, and the scale reads 10kg.

You then climb a very high mountain with scale and water record the reading.

You then journey down a very deep mine shaft and take another recording.

Multi Choice, do the readings ON THE SCALES show...
a) Heavier both up the mountain and down the mine shaft
b) Lighter both up the mountain and down the mine shaft
c) Heavier up the mountain and lighter down the mine shaft
d) Lighter up the mountain and heavier down the mine shaft

I will give it a couple of days then if the correct answer is not posted with the explaination I will....

[gatch]

Is this a trick ?

Wouldn't the mass stay the same..

[bogan]

im going to go with d) as i reckon the pressure head from the atmosphere will have a larger affect than the change in gravity at different altitudes.

[bogan]

Is this a trick ?

Wouldn't the mass stay the same..

the mass will, but the scales will read the weight different i reckon

[Big Dave]

Deefer for David

[LBD]

Is this a trick ?

Wouldn't the mass stay the same..

No its not a trick question, yes the mass would stay the same, the scales change...have clarified in the question

the mass will, but the scales will read the weight different i reckon

yep its as simple as the question now reads.

There is a simple logical factual answer...

[Jantar]

Very simple. The scales will show a lighter weight at both locations. (answer b).

If the mountain could be as high as 35,700 km (at the equator) then the water would be weightless. Similarly if the mine shaft went right to the center of the earth then it would again be weightless.

[Hans]

Nope. Gravitational field of the Earth diminishes with distance. However, the higher and therefore more massive the mountain, the more you'd have to factor in the gravitational force of the mountain itself. As for the mine shaft, I'm guessing the deeper you went the more the gravitational force would change direction, rather than intensity. Sum of intensities of different directions shouldn't change much. I'd rather noone quoted me on any of this, it's half past midnight.

[Jantar]

Nope. ......

Yep. It was one of the first discussions we had in year 1 physics back in 1971.

First; the mountain: Because it is a mountain it is steep, and the circumference of the base can never be greater than the circumference of the earth. The center of mass of the entire system cannot be more than 1/8 (volume of a cone) of the distance from the present center of the earth to the top of the mountain, so the water is significantly further away from the center of mass and the gravitional effect is reduced.

In the mineshaft there is mass above which is pulling upwards, and at the center of the earth all gravitational effects are balanced.

[TOTO]

I go for answer D.

If the earth centre core is a magnet, up high at the mountain , it is further from the magnet, thereofre less gravitational pull, and down the shaft it is closer to the magnet, hence scale will read a heavier weight.

did I win the $100 000 or I have to go get married in the nude ?

[Jantar]

I go for answer D.

If the earth centre core is a magnet, up high at the mountain , it is further from the magnet, thereofre less gravitational pull, and down the shaft it is closer to the magnet, hence scale will read a heavier weight.

did I win the 100 000 or I have to go get married in the nude ?

Where do I get this water that is attracted to a magnet?

[TOTO]

Where do I get this water that is attracted to a magnet?

tap water will do.

[Big Dave]

Where do I get this water that is attracted to a magnet?

Lake Macquaire - Just near the smelter and cooling outlet for the Power Station.

[Hans]

Yep. It was one of the first discussions we had in year 1 physics back in 1971.

First; the mountain: Because it is a mountain it is steep, and the circumference of the base can never be greater than the circumference of the earth. The center of mass of the entire system cannot be more than 1/8 (volume of a cone) of the distance from the present center of the earth to the top of the mountain, so the water is significantly further away from the center of mass and the gravitional effect is reduced.

In the mineshaft there is mass above which is pulling upwards, and at the center of the earth all gravitational effects are balanced.

Fail. In the mineshaft gravity will also act sideways, not just up or down. Also thread/question fail IMHO. please set some proper paramaters for the question. Ie. what to regard/disregard, how high, how deep etc. Let's not do kindy-physics. Some considerations change the outcome.

[Jantar]

Fail. In the mineshaft gravity will also act sideways, not just up or down. Also thread/question fail IMHO. please set some proper paramaters for the question. Ie. what to regard/disregard, how high, how deep etc. Let's not do kindy-physics. Some considerations change the outcome.

Oh dear. Draw the vector diagram. Exact values are not required because on the surface of the earth there is no upwards attraction vector. Yes there are some almost sidewards ones that cancel each other out. As you get deeper the integral of all vectors reduces as the strength of the upwards increases. Again all sidewards cancel out.