**Applied Maths Before/After**

Bionicle

The answer to Q7. (a) is cos inverse 7/15. If you did physics, you should know that from the experiment, the magnitude of the resultant of the 5N force and 12N force is the 15N force and it acts in the opposite diretion. I Let 12N force be a horizontal force whose vector co=ordinates are 12i and let the 5N force's vector foce be 5cos(theta)i + 5sin(theta)j. Find their sum and then find the magnitude of the sum and let it equal 15. Solve that equation and you should get the answer.

Undeadfred

Bionicle wrote: »

The answer to Q7. (a) is cos inverse 7/15. If you did physics, you should know that from the experiment, the magnitude of the resultant of the 5N force and 12N force is the 15N force and it acts in the opposite diretion. I Let 12N force be a horizontal force whose vector co=ordinates are 12i and let the 5N force's vector foce be 5cos(theta)i + 5sin(theta)j. Find their sum and then find the magnitude of the sum and let it equal 15. Solve that equation and you should get the answer.

Damn, i really should have left it as the diagram showed it. I copied it down in my answer booklet with the 15N force horizontal thinking it would be easier. ugh...

Bionicle

Does anyone want answers to Q8?

lostatsea

Undeadfred wrote: »

I also did this but it lead to some very ugly and long equations that took ages to figure out. Don't have a clue how to do it the way lostatsea says

Solution attached:

Deathrae1

Did anyone do question 9b and if so what answer did you get? I went into the paper thinking I was going to fail but I found the paper to be easier than previous years! It was different but I thought that was for the better.

lostatsea

Deathrae1 wrote: »

Did anyone do question 9b and if so what answer did you get? I went into the paper thinking I was going to fail but I found the paper to be easier than previous years! It was different but I thought that was for the better.

Question 9(b): a = 0.4

Undeadfred

lostatsea wrote: »

Solution attached:

God that's so simple. You should have seen the amount i wrote, almost 2 pages of huge long trig equations

no scope codgod

lostatsea wrote: »

Question 9(b): a = 0.4

400 I think?

Glee_GG

Bionicle wrote: »

Does anyone want answers to Q8?

Yes please!

Bionicle

(i)2pisqrt(2r/g) and (ii) l=2r for q8 (b).

xJEx

Bionicle wrote: »

(i)2pisqrt(2r/g) and (ii) l=2r for q8 (b).

I don't think that is correct

Bionicle

xJEx wrote: »

I don't think that is correct

I wasn't sure either as I am very rusty on inertia. I'll look over it again however as I was surprised how nice the answers were.

Bionicle

Apologies, I used the wrong formula.:P

The answers are actually:

(i)2pisqrt(5r/3g)
(ii)l=5r/3

Glee_GG

Bionicle wrote: »

Apologies, I used the wrong formula.:P

The answers are actually:

(i)2pisqrt(5r/6g)
(ii)l=5r/6

Can you throw up a pic of the solution please

Bionicle

Glee_GG wrote: »

Can you throw up a pic of the solution please

Ugh I edited my solution cuz I was justdoingrough work and mixed up numbers. :P

Bionicle

Okay, I wrote out my solution nicely soI can confirm the answers. If there is a problem, let me know.

xJEx

Bionicle wrote: »

Apologies, I used the wrong formula.:P

The answers are actually:

(i)2pisqrt(5r/3g)
(ii)l=5r/3

That's more like it

lostatsea

Bionicle wrote: »

Apologies, I used the wrong formula.:P

The answers are actually:

(i)2pisqrt(5r/3g)
(ii)l=5r/3

Those answers are correct