need help with Physics homework

[redlineranger]

im not a numbers or science person so this class is going to be extremely hard for me. i have a couple of questions and i'll try to present the numerical problems the best i can.

heres one..

Convert 92 X 10^3 km to decimeters using scientific notation.[the ^ stands for exponent, like 10 to the third power]

heres another..

Calculate the following, expressing the answer in scientific notation with the correct number of significant figures:[8.86 + 1.0 X 10^-3] / 3.160 X 10^3 the / stands for division

[powermadd400ex]

:eek2:
and i thought my honors chemistry was bad

[redlineranger]

Originally posted by powermadd400ex
:eek2:
and i thought my honors chemistry was bad

i had an extremely hard time in chemisty to.. im good at history and english, not science and math lol.

[powermadd400ex]

Originally posted by redlineranger
i had an extremely hard time in chemisty to.. im good at history and english, not science and math lol.

haha tell me about it, its memorizing the converting things that kill me.
do you get to use a calculator in physics?

[redlineranger]

Originally posted by powermadd400ex
haha tell me about it, its memorizing the converting things that kill me.
do you get to use a calculator in physics?

oh yea.. without a calculator the numerical problems would be impossible. well to me anyways.

if anyone can help thanks in advance

[atvmaster0927]

Originally posted by redlineranger
im not a numbers or science person so this class is going to be extremely hard for me. i have a couple of questions and i'll try to present the numerical problems the best i can.

heres one..

Convert 92 X 10^3 km to decimeters using scientific notation.[the ^ stands for exponent, like 10 to the third power]

heres another..

Calculate the following, expressing the answer in scientific notation with the correct number of significant figures:[8.86 + 1.0 X 10^-3] / 3.160 X 10^3 the / stands for division

The first one is 92000. (i learned this one in i think 8th grade science lol).

The second one is 2804.113924 I THINK.

I used my $150 calculater for the second one lol.

I take physics next year in 11th grade.

[redlineranger]

Originally posted by atvmaster0927
The first one is 92000. (i learned this one in i think 8th grade science lol).

The second one is 2804.113924 I THINK.

I used my $150 calculater for the second one lol.

I take physics next year in 11th grade.

yea i get joked on because i simply just dont comprehend math or science, and then when you put both together im really f*cked :scary: .. i feel so dumb in my class and i hear about it too so i pretty much have to tell everyone to kiss my *ss

but anyways thanks.

[atvmaster0927]

Originally posted by redlineranger
yea i get joked on because i simply just dont comprehend math or science, and then when you put both together im really f*cked :scary: .. i feel so dumb in my class and i hear about it too so i pretty much have to tell everyone to kiss my *ss

but anyways thanks.

Yup no problem. All you have to do is really plug everything into the calculater and your done.

[snacob14]

first one is converting 92x10^3 = 92000
then you must convert km to dm remember this...
king henry drinks many double chocolate milks
kilo/hecto/deci/m/deci/centi/milli

moving across the metric conversion chart four spaces adds four zeros
920000000.00 new scientific notation
9.2 x 10^8
6th grade math...

[snacob14]

the second problem is just order of operations====
Please Excuse My Dear Aunt Sally

Parentheses, Exponents, Multiplication, Division, Addition, Subtraction

these are things that are easy to forget, but also easy to remember because they don't get practiced much.

[Quad18star]

For the second question i got 3.120253165x10^-6

.00986/3160 = number above. So if you need to round off to the right number of decimals ... you gotta go with 3 digits after the point since in your equation one of the numbers has 3 digits .

First question is 92 000KM , converted is 920 000 000 .... so being there is 8 zeros it's 92*10^8

[400exMO]

Read your physics book, it will tell you all the answers. This is stuff you will need have as second nature in college.

The second question states using sig figures, nobody was right. Read your book, no better way to learn.

[400exMO]

Also on the first one you need to remember they are both in meters. The metric system uses prefixs to denote values. Kilo is one thousand and deci is one tenth (1/10), convert from there.

[wilkin250r]

Originally posted by Quad18star
For the second question i got 3.120253165x10^-6

.00986/3160 = number above. So if you need to round off to the right number of decimals ... you gotta go with 3 digits after the point since in your equation one of the numbers has 3 digits .

First question is 92 000KM , converted is 920 000 000 .... so being there is 8 zeros it's 92*10^8

Close. There's only seven zeros, so it's 92 x 10^7 (which is actually the same as snacob14's answer of 9.2 x 10^8, notice the decimal point)




As for the second question, the calculations are only half the problem. The REAL question is the topic of significant digits.



Imagine I said it's 240,000 miles to the moon. Do the calculations, and it becomes 15206400000 inches. Now, who honestly believes that's 100% dead accurate? That it's not 15206400001 inches, or 15206399999 inches?


Your resulting calculations cannot be MORE accurate than your orignal measurement. If your original measurement could be off a couple hundred miles, you can't give an answer accurate down to an inch, it's not meaningful.

The rule of thumb is that you answer must contain the same amount of significant digits as the LEAST number of significant digits in your original calculations.

In the original question, the term 1.0x10^-3 has only two significant digits, so your ANSWER can only have two significant digits.

Getting rid of the scientific notation, the problem reduces to 8.861/3160, which equals 0.002804113924. But we're limited to two significant digits, so you have to get rid of the rest of that garbage, 2.8 x 10^-3 is the final answer.

[redlineranger]

thanks for the help everyone. i went back last night and re worked them and got most of them right. its just the complex numbers and other things of that nature gets me so confused and aggravated that i just say to hell with it.

and i deffinately don't remember doing any of this in 6th grade math snacob14.

math didnt start getting hard for me until the 9th grade. from there on its been a struggle, but i usually maintained a 80-88 average which in Alabama is "B".

science has always been easy up until last year in 11th when i started chemistry. biology and anatomy and physiology were gravy. but chemisty and physics just has thrown me for a loop

[snacob14]

well, I teach six grade math, and we discuss order of operations and scientific notation. I'm assuming your physics class is just starting. You're probably just doing some reviewing of basic concepts before it gets hard