Estimate the pressure exerted on a floor

In summary: Therefore, the weight is distributed over that one foot, not all four. In summary, the problem is asking for an estimate of the pressure exerted by a pointed chair leg (with a weight of 66 kg distributed equally over 4 legs) and a 1300-kg elephant standing on one foot. The equation used is P=F/A=W/A, and the answer is found by using 1/4 of the weight of the chair leg and the full weight of the elephant. This is because the elephant is standing on only one foot, while the chair is supported by four legs.
  • #1
Neon32
68
1

Homework Statement


3. (I) Estimate the pressure exerted on a floor by (a) one pointed chair leg (66 kg on all four legs) of 2 area  0.020 cm , and (b) a 1300-kg elephant standing on one foot   2 area  800 cm .

Homework Equations


P=F/A=W/A

The Attempt at a Solution



I know the solution. But I don't understand why in (a) we used the mass of one leg and on (b) we used the mass of the whole elephant..even though the elepahnt was standing on one foot just like the chair was standing on one leg.[/B]
 
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  • #2
Well, the problem statement dictates it. Striking that an elephant exercises less pressure with one foot than a chair with 4 !

It explains nicely why our wooden floor only has lots of imprints from the visiting ladies with stiletto heels and none from the elephants :smile:

I do have trouble reading off the areas, though. ##0.02## cm2 doesn't feel right.
 
  • #3
The wording for the chair leg is kind of unclear. There are two possibilities: 1) There is a total of 66 kg spread out equally over 4 of the chair legs, or 2) each chair leg supports 66 kg. It appears that each leg is supporting 66 kg, based on where you said, "in (a) we used the mass of one leg".
 
  • #4
TomHart said:
The wording for the chair leg is kind of unclear. There are two possibilities: 1) There is a total of 66 kg spread out equally over 4 of the chair legs, or 2) each chair leg supports 66 kg. It appears that each leg is supporting 66 kg, based on where you said, "in (a) we used the mass of one leg".
All 4 legs support 66 kg so one leg support 1/4 x 66
 
  • #5
BvU said:
Well, the problem statement dictates it. Striking that an elephant exercises less pressure with one foot than a chair with 4 !

It explains nicely why our wooden floor only has lots of imprints from the visiting ladies with stiletto heels and none from the elephants :smile:

I do have trouble reading off the areas, though. ##0.02## cm2 doesn't feel right.
I mean in the answer he used 1/4 times 66 to find the mass on one leg.

But in (b) he used the whole mass of the elephant while it was on one foot..why he didn't use 1/4 times mass of the elephant? considering that the elephant has 4 legs?
 
  • #6
Neon32 said:
why he didn't use 1/4 times mass of the elephant? considering that the elephant has 4 legs?

It says the elephant is standing on one foot.
 

1. What factors contribute to the pressure exerted on a floor?

The amount of weight or force applied to the floor and the surface area of contact are the two main factors that contribute to the pressure exerted on a floor. Other factors such as the type and condition of the flooring material can also affect the pressure.

2. How is pressure calculated on a floor?

Pressure is calculated by dividing the force or weight exerted on the floor by the surface area of contact. The unit of measurement for pressure is typically pounds per square inch (psi) or Newtons per square meter (N/m2).

3. What are some common ways to measure the pressure on a floor?

There are a few methods to measure the pressure on a floor, including using pressure sensors, load cells, or strain gauges. These devices can provide accurate measurements of the force applied to the floor and the resulting pressure.

4. How does the distribution of weight affect the pressure on a floor?

The distribution of weight on a floor can significantly impact the pressure exerted. For example, if a heavy object is placed on a small surface area, it will exert a higher pressure than if the same weight was distributed over a larger surface area.

5. Can the pressure on a floor be too high?

Yes, the pressure on a floor can be too high, and this can lead to damage or failure of the floor. It is essential to ensure that the weight or force applied to a floor is within the recommended limits to prevent excessive pressure and potential structural issues.

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