Physics homework problem

[hot commodity]

Question:

An interior staircase has steps with a rise(height of step) of 18.5cm and a run(depth of step) of 21.9cm. The height of the staircase is 4.07m. It is desired to make the run of a new staircase 27.4cm. How much farther into the room will the new staircase go? (Answer to be in meters).

I'm not asking for the answer, I'm just having a hard time picturing the problem and understansing what they're asking for.

[learnin to learn]

it is basically saying that you increase the width of each individual stair.

[hot commodity]

Okay, looks like I'm going to need more than a hint, if anyone can help...

[Sleeth]

Question:

An interior staircase has steps with a rise (height of step) of 18.5cm and a run (depth of step) of 21.9cm. The height of the staircase is 4.07m. It is desired to make the run of a new staircase 27.4cm. How much farther into the room will the new staircase go? (Answer to be in meters).


First you will need to find out how many steps there are (They must be in the same units first):

Number of steps=hight of staircase/hight of staircase
=407(cm)/18.5(cm)
=22 steps

Next you need to find out how far it will go into the room:

How far into room (new staircase)=number of steps*new run of step
=22*27.4(cm)
=602.8 cm

Now you need to find out the difference to find out how much further into the room it will protrude:

How much further into room=how far into room (new staircase)-how far into room (old staircase)
=602.8(cm)-407(cm)
=195.8(cm)
=1.958(m)
=1.96 m

Its just basic maths. Next time, do it yourself. It doesn't help you at all by having other people do it for you!

[hot commodity]

I did somewhat the same thing but got 1.21m, I'll have to go back and check my work. But thanks for the help = )

[InfiniteNow]

Originally Posted by hot commodity

I'm not asking for the answer, I'm just having a hard time picturing the problem and understansing what they're asking for.

Originally Posted by Sleeth

Its just basic maths. Next time, do it yourself. It doesn't help you at all by having other people do it for you!

[cwes99_03]

Careful Sleeth. You are a newcomer and haven't yet earned a reputation or the status of Mod (but then nor have I and I have also chastised some for their posts, as I am kind of doing now.)
This person is new and asked a pretty simple question. The aim would be to help them figure it out for themselves, not to do it for them. I only chastise those who come back over and over and over and keep on asking the same easy questions. For these I suggest a tutor, but some on this site are willing to be that very tutor.

The question was pretty simple. The first stair case had a certain number of treads and had a certain depth, while the new staircase would have the same number of treads (since the rise was not adjusted) but would go deeper into the house requiring a larger footprint on the plans. Hot commodity obviously didn't get the number of treads correct and thus didn't get the expected answer. Maybe he need try harder, but then again he may have tried over and over and come up with the same answer.

Likely he failed to take into account the top or bottom landing, or possibly he took them into account and they were not required to be. The bottom landing is likely already part of the floor, as well as the top landing is likely part of the next floor, thus they are not considered in the depth measurement, but then the writer of the question may not have considered this either. It is about building technique.
When that additional tidbit is taken into the equation there are actually two different correct answers.

Instead of giving the height of the run (even though it won't change) they should have given the current depth of the run. This for sure would have only left one possible answer.

[hot commodity]

When the problem said "farther into the house," I assumed it meant the lentgh of the bottom of the staircase. So I figured it to be the length of the new staircase (602.8cm) minus the old length (481.8cm), and then converting that to meters you get 1.21m. Maybe I'm missing something, but I thought I had the right answer

edit: I found the answer, apparently there are two answers. the trick is there are 22 steps implied, but they were looking for you to do the problem where there are 22 rises, and 21 runs.

[cwes99_03]

That is what I pointed out. Technically there is a third solution. Where before the first rise, you have a run, and after the last rise you have a run.

Sounds like they were wanting just the runs between the rises and not part of any landing.

[Sleeth]

Actually, I made a blatantly obvious mistake. I found out the length of the stairway and took away the hight of the stairway, instead of the original lenght (which you also have to figure out). Hot commodity's answer should be right. In which case I did not need to write what I did, but I was curious to see whether or not anyone realised.

In any case I am not spamming! (Just incase!)

Also, hot commodity is not a new member, he used to be a member known as hotcommodity! He told everyone in the introductions forum, if anyone read it.