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Question

Please do your best to answer either of these questions(: Remember, these are physics questions! Try to answer in physics terms.

A stonecutter's chisel has an area of .5 cm^2. If the chisel is struck with a force of 45 N, what is the pressure exerted on the stone? (answers must be in N/m^2)

Which is more likely to hurt?

1. being stepped on by a 200 lb man wearing flat soled shoes

2. being stepped on by a 100 lb woman wearing high heeled shoes

Answer 1

High heels. More pressure on a small area.

Answer 2

Idk i would think number 2, but a 100 lb women isnt very heavy. But then again its only hitting one small area so yeah i would say number two.

Answer 3

definitly 2

Answer 4

1. .5cm^2 = .00005m^2

45N/.00005m^2 = 900000 N/m^2

2. 2 would hurt more, it is a smaller force but the 200lb man has his force spread out over a far larger surface area than the 100lb woman with the high heeled shoes.

Answer 5

pressure = force/area [p=f/a].

The pressure is indirectly proportional to the are. [When the area decreases, the pressure increases.

p=45N/05.0 × 10-5m^2

p=900 000N/m^2

2.

If the area decreases pressure increases.

High heels have a very small area compared to flat shoes.

Answer 6

The key to questions like the first one is to look at the units in the given values and the requested answer. You are given a force in Newtons and an area in cm^2. The answer must be in N/m^2 so it looks like we're going to divide the Newtons by the area.

0.5cm^2 is 0.00005m^2.

From the units of the answer you can see the Newtons must go on the top and the area on the bottom. Also, the bigger the force (N) the bigger the pressure (think about it) so the N must go on the top. Also if the same force was applied to a football field it would be negligible, so the bigger the area, the smaller the pressure (think of a hammer hitting a sheet of metal the size of a football field - pathetic!)

So, 45N/0.00005m^2 = 900000N/m^2

= 9x10^5N/m^2

Using the intuition from the first part you can attempt to answer the second part. Actually it's a sloppy question, because they don't say whether it's the sole or the heel of the high-heeled shoe. We'll give them the benefit of the doubt and assume heel.

The weight (force) of the woman is half that of the man, but the area is far far less for a stiletto heel compared to a normal heel. Pressure is force/area (remember the football field) so if the area is much less (say 1/10th)

and area is on the bottom, then pressure is much higher (5x). So it's the woman who hurts more.

If in doubt during an exam about these principles think of an extreme. If I push a coin onto your hand with all my power it might be uncomfortable because a coin is quite small. But if I push a needle onto your hand with all my power it's going to hurt big time. Smaller area (needle point) = more pressure for the same applied force.

Answer 7

First the question one and two don't have enough parameters.

What size shoe is the man wearing?

What size shoe is the woman wearing and what type of heel?  the heel can be from a 1/4 inch to up to 3/4 inch by 1 1/2 inches in size and still be a high heel.  Also with the womans shoes with the weight be evenly distributed or will more weight be on the toe or the heel on the womans shoes?

Answer 8

"Which is more likely to hurt?"

Let's just say how often do you get stepped on by the heel of someone's shoes? I'd go for the fat man.

Answer 9

90N/m^2

and number 2