Question

I am not too good with these...did I do this right...can you work it out with proportions ??

Answer 1

in a spring the tension (T newtons) is directly proportional to its extension (xcm) When the tension is 150 newtons, the extension is 6cm (a) Find a formula for T in terms of x. T= ....?
(B) calculate the tension, in newtons, when the extension is 15 cm newtons...?
(C) calculate the extension in cm, when the tension is 600 newtons ....cm


This is what I did...
150 newtons (T) = 6 cm (a)
150T = 6a
T = 6a/150

B. 150/6 = x/15
cross multiply
6x = (150)(15)
6x = 2250
x = 375 newtons

C. 150/6 = 600/x
cross multiply
150x = (6)(600)
150x = 3600
x = 3600/150
x = 24 cm

Answer 2

@AccessDenied ....can you take a peek at this

Answer 3

@kropot72 ...is this correct ??

Answer 4

can this be solved with proportions or do I have to use the y = kx thing

Answer 5

@mathmale .....

Answer 6

I just noticed the first part is wrong....formula for T in terms of x....it can't be T = (6a)/150

Answer 7

This is what I did...
150 newtons (T) = 6 cm (a)
150T = 6a
T = 6a/150
Can you say what it is that you're looking for here? What's your purpose?
You are given T and x (x being the extension); you are trying to find what quantity?

Answer 8

I do not know...I do not know how to do the y = kx thing ??

Answer 9

looking for the constant of proportionality ??

Answer 10

so is y newtons and the extension x ?

Answer 11

that "y=kx thing" is exactly what you need. k is called "the constant of proportionality." Your job is to find k first, and then write a linear equation involving y, x and that k value.
Try again: If T=150N and x=the spring extension= 6 cm., what is k?

Answer 12

y = kx
150 = 6k
150/6 = k
25 = k ??

Answer 13

Yes, that's right. Now, with independent variable x and dependent variable T, write the required equation for T in terms of k and x.

Answer 14

T = 25x ?? Am I way off on this ??

Answer 15

Not at all. Come on, show more confidence!

Answer 16

so that would be the answer for the first part ??

Answer 17

or would it be : x = T/25

Answer 18

Look what you're trying to do:

(B) calculate the tension, in newtons, when the extension is 15 cm newtons...?


Using your new formula (answer for Part A), substitute x=15 cm and calculate T. Be certain to use the correct units of measurement.

Answer 19

T = 25x
T = 25(15)
T = 375 newtons

thats what I got by doing a proportion.

T = 25x
600 = 25x
600/25 = x
24 cm = x

ok....I see now.

Thank you so much mathmale :)

Answer 20

My great pleasure! MM