A level maths mechanics help!!
hi guys, been having a hard time with maths, i can do complex problems but not basic math. need help with this question from the textbook mixed exercise 8 mechanics:
Q4) Convert to SI units: 0.6 kg cm^-2
It needs to be in kg m^-2, but how do you do it like i dont understand why ppl are multiplying it by 10000 or whatever pls tell me in detail the steps tysmm
Q4) Convert to SI units: 0.6 kg cm^-2
It needs to be in kg m^-2, but how do you do it like i dont understand why ppl are multiplying it by 10000 or whatever pls tell me in detail the steps tysmm
Scroll to see replies
The basic here is that you need to covert from cm^2 to m^2. The way i like to do this is to think about what this would look like in terms of area. Imagine you have a square with 1m length each side and so the area is 1m^2. What’s the area if you do this with the units of the sides being in cm so the area can be written in cm^2?
Does that help?
Does that help?
Original post by cupcakeglorious6
hi guys, been having a hard time with maths, i can do complex problems but not basic math. need help with this question from the textbook mixed exercise 8 mechanics:
Q4) Convert to SI units: 0.6 kg cm^-2
It needs to be in kg m^-2, but how do you do it like i dont understand why ppl are multiplying it by 10000 or whatever pls tell me in detail the steps tysmm
Q4) Convert to SI units: 0.6 kg cm^-2
It needs to be in kg m^-2, but how do you do it like i dont understand why ppl are multiplying it by 10000 or whatever pls tell me in detail the steps tysmm
right so there are 100 centimetres in a metre, which is using 1 dimensional units. Metres squared is a 2 dimensional unit so you need to raise the number of centimetres in a metre to the power of two (i.e. 10,000 cm^2 in 1 m^2 from 100 cm in 1m) The fact that its area to a negative power doesn't really affect the way you deal with it here.
6 x 10^-1 kgcm^-2 is equal to 6 x 10^-6 kgm^-2. You're dividing by 10000.
You can kinda mentally justify it by thinking if you have one kilo on an area of one centimetre squared, thats one kilo on a metre squared, so you divide by the number of centimetres squared in a metre squared.
(edited 1 month ago)
Original post by hedhoj
right so there are 100 centimetres in a metre, which is using 1 dimensional units. Metres squared is a 2 dimensional unit so you need to raise the number of centimetres in a metre to the power of two (i.e. 10,000 cm^2 in 1 m^2 from 100 cm in 1m) The fact that its area to a negative power doesn't really affect the way you deal with it here.
6 x 10^-1 kgcm^-2 is equal to 6 x 10^-6 kgm^-2. You're dividing by 10000.
You can kinda mentally justify it by thinking if you have one kilo on an area of one centimetre squared, thats one kilo on a metre squared, so you divide by the number of centimetres squared in a metre squared.
6 x 10^-1 kgcm^-2 is equal to 6 x 10^-6 kgm^-2. You're dividing by 10000.
You can kinda mentally justify it by thinking if you have one kilo on an area of one centimetre squared, thats one kilo on a metre squared, so you divide by the number of centimetres squared in a metre squared.
thats what i thought too but apparently the answer is 6000
Original post by DerDracologe
The basic here is that you need to covert from cm^2 to m^2. The way i like to do this is to think about what this would look like in terms of area. Imagine you have a square with 1m length each side and so the area is 1m^2. What’s the area if you do this with the units of the sides being in cm so the area can be written in cm^2?
Does that help?
Does that help?
so it would be 10000cm^2, but i thought u divide by 10000 but apparently its multiply by 10000, why do they multiply?
Original post by cupcakeglorious6
so it would be 10000cm^2, but i thought u divide by 10000 but apparently its multiply by 10000, why do they multiply?
Sorry for creating confusion, i didnt want to tell you the steps directly so you can work it out for yourself- i was just explaining how i think about converting between the squared units.
If you think about it, the unit you start with is in cm^2 1cm=0.01m and so the square would have the side length of 0.1m. Then you find the area to get the conversion factor and use that.
Sorry if ive made it more complicated but its how i think about it….
Original post by DerDracologe
Sorry for creating confusion, i didnt want to tell you the steps directly so you can work it out for yourself- i was just explaining how i think about converting between the squared units.
If you think about it, the unit you start with is in cm^2 1cm=0.01m and so the square would have the side length of 0.1m. Then you find the area to get the conversion factor and use that.
Sorry if ive made it more complicated but its how i think about it….
If you think about it, the unit you start with is in cm^2 1cm=0.01m and so the square would have the side length of 0.1m. Then you find the area to get the conversion factor and use that.
Sorry if ive made it more complicated but its how i think about it….
no worries could you explain step by step how to solve it please?
Ive done the question and here are the steps:
I can confirm that as the OP said, the answer is 6,000 as far as ive worked out
1.
Find the conversion factor to get from 1cm^2 to 1m^2
2.
Write the unit for m^2 in terms of cm^2
3.
Substitute this into the original unit
sorry could u write the numbers as well so it makes sense to me ? thanks!
Original post by cupcakeglorious6
no worries could you explain step by step how to solve it please?
I’ve written out the steps, if youre still stuck i can go through it in full seen as you already gave the answer (not giving people the answers to questions but i think i can explain why an answer fits a question)
Original post by DerDracologe
I’ve written out the steps, if youre still stuck i can go through it in full seen as you already gave the answer (not giving people the answers to questions but i think i can explain why an answer fits a question)
yes please because then like is there a specific method? bc i wasnt taught any like methods and stuff and if u could do as above too like write the numbers
Original post by cupcakeglorious6
sorry could u write the numbers as well so it makes sense to me ? thanks!
Find the conversion factor:
1cm=0.01m so as per the area finding method, 1cm^2=(0.01)^2m^2 which is 10^-4m^2
Write out 1m^2 in terms of cm^2:
1cm^2=10^-4m^2 so 1m^2=1/10^-4 cm^2
Substitute back into the original unit:
0.6kg*1/10^-4m^2 = 0.6kg*10^4m^2 = 6000kgm^2
Original post by cupcakeglorious6
yes please because then like is there a specific method? bc i wasnt taught any like methods and stuff and if u could do as above too like write the numbers
Not really a method, just logic to convert the units and then algebraic manipulation (just like writing an expression in terms of a different value to the one given as im sure you’ll have plenty of experience of from gcse!)
Original post by DerDracologe
Find the conversion factor:
1cm=0.01m so as per the area finding method, 1cm^2=(0.01)^2m^2 which is 10^-4m^2
Write out 1m^2 in terms of cm^2:
1cm^2=10^-4m^2 so 1m^2=1/10^-4 cm^2
Substitute back into the original unit:
0.6kg*1/10^-4m^2 = 0.6kg*10^4m^2 = 6000kgm^2
1cm=0.01m so as per the area finding method, 1cm^2=(0.01)^2m^2 which is 10^-4m^2
Write out 1m^2 in terms of cm^2:
1cm^2=10^-4m^2 so 1m^2=1/10^-4 cm^2
Substitute back into the original unit:
0.6kg*1/10^-4m^2 = 0.6kg*10^4m^2 = 6000kgm^2
omg that is such a smart way to do it, like ive never heard of it but it kind of makes sense now like u divide it by that number to make the other side one and stuff, ill try to see if it works with the other ones and if i need any more help i will let u know but THANK YOUU iwas legit crying like a level maths is so difficult man how ru so smartttttt lol
Original post by DerDracologe
Not really a method, just logic to convert the units and then algebraic manipulation (just like writing an expression in terms of a different value to the one given as im sure you’ll have plenty of experience of from gcse!)
gcse i just self taught a bit cuz my teacher was never in, all the topics i loved came up so got lucky with a 9 and now i am struggling in a level any youtubers recommendations? also do u get the textbook questions wrong quite a bit as well like omg proof in chapter 7 pure is acc so baddd like some of it (i dont get when u can use numbers to prove and when u have to use algebra) also do u do bio or chem
Original post by cupcakeglorious6
omg that is such a smart way to do it, like ive never heard of it but it kind of makes sense now like u divide it by that number to make the other side one and stuff, ill try to see if it works with the other ones and if i need any more help i will let u know but THANK YOUU iwas legit crying like a level maths is so difficult man how ru so smartttttt lol
Glad i could help! I always find it helps to visualise a problem like this to work it out 🙂 Best of luck with a level maths!
Original post by cupcakeglorious6
gcse i just self taught a bit cuz my teacher was never in, all the topics i loved came up so got lucky with a 9 and now i am struggling in a level any youtubers recommendations? also do u get the textbook questions wrong quite a bit as well like omg proof in chapter 7 pure is acc so baddd like some of it (i dont get when u can use numbers to prove and when u have to use algebra) also do u do bio or chem
Ive heard good things about Bicen maths (hope that’s spelled right) but to be honest I haven’t watched any videos yet. Ive looked at the CGP textbook i have to write up notes but to be honest im quite lucky because so far there hasn’t been any content that’s stumped me. I did fsmq (self-taught the vast majority of the content) in year 11 so that’s really helping especially as i somehow got an A!
Do you do OCR? I dont actually have a textbook yet 😬 My class were given them but i didnt go into that lesson (i have sensory differences so i struggle with school quite a lot annoying) so i dont have a copy atm. I should probably ask for one when i get back to school! I do make a lot of silly errors on questions though (kinda my speciality!). It became a bit of a running joke with my friends because I haven’t had a maths test come back since year 9 on which the feedback said anything other than check your working or read the questions carefully lol.
Let me know on pm if you need any help with the proof stuff btw- cant promise ill know how to explain but can give it my best shot!
I do Biology and Physics with Maths. How about you? Im assuming bio, chem and maths?
Btw I have a gyg (Link here) if you wanna follow cos ill mention resources im using and stuff like that on there- or if you want to discuss subjects and stuff if you dont wanna message me.
(edited 1 month ago)
Original post by cupcakeglorious6
hi guys, been having a hard time with maths, i can do complex problems but not basic math. need help with this question from the textbook mixed exercise 8 mechanics:
Q4) Convert to SI units: 0.6 kg cm^-2
It needs to be in kg m^-2, but how do you do it like i dont understand why ppl are multiplying it by 10000 or whatever pls tell me in detail the steps tysmm
Q4) Convert to SI units: 0.6 kg cm^-2
It needs to be in kg m^-2, but how do you do it like i dont understand why ppl are multiplying it by 10000 or whatever pls tell me in detail the steps tysmm
Hello!
I hope I understood your question correctly.
To resolve equivalences between surface measurements in the International System between km2 and mm2, we can use the method of the square metre. This involves drawing a real scale and, at each step, indicating the multiples and submultiples of the square metre, from the square kilometre to the square millimetre, in an orderly way, as shown in the figure below.
In area measurement, each unit is 100 times larger than the previous and 100 times smaller than the next. This means that to go from one unit of measurement to the next, we have to multiply by 100; to go from one unit of measurement to the previous one, we have to multiply by 100.
Once this is done, it is sufficient to count the number of steps that separate the two units of measurement between which we wish to establish equivalence, and
- divide by 100 raised to the number of steps if we are ascending;
- multiply by 100 raised to the number of steps if we are descending.
Note: In the case where the number is a decimal number, if we are descending, we move the point to the right, and if we are ascending, we move the point to the left.
EDIT: Source: literal translation of an Italian book on arithmetic.
Bye,
Sandro
(edited 1 month ago)
Original post by DerDracologe
Find the conversion factor:
1cm=0.01m so as per the area finding method, 1cm^2=(0.01)^2m^2 which is 10^-4m^2
Write out 1m^2 in terms of cm^2:
1cm^2=10^-4m^2 so 1m^2=1/10^-4 cm^2
Substitute back into the original unit:
0.6kg*1/10^-4m^2 = 0.6kg*10^4m^2 = 6000kgm^2
1cm=0.01m so as per the area finding method, 1cm^2=(0.01)^2m^2 which is 10^-4m^2
Write out 1m^2 in terms of cm^2:
1cm^2=10^-4m^2 so 1m^2=1/10^-4 cm^2
Substitute back into the original unit:
0.6kg*1/10^-4m^2 = 0.6kg*10^4m^2 = 6000kgm^2
wait i just realised i dont think u did it to ^-2, i think u did ^2 , so would it be different to the ^-2 as that what the question says?
Original post by cupcakeglorious6
wait i just realised i dont think u did it to ^-2, i think u did ^2 , so would it be different to the ^-2 as that what the question says?
Oh yes… very sorry! Somehow however ive got the right answer lol. See what i mean about not reading the question….
Updated method without me multitasking lol:
Find the conversion factor:
1cm=0.01m so 1cm^-2=(0.01)^-2m^2 which is 10^4m^2
Substitute back into the original unit:
0.6kg*10^4m^2 = 0.6kg*10^4m^2 = 6000kgm^2
Again, huge apologies for my earlier errors- i worked backward from the answer as you gave it to save time but misread the question 😅
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