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# Help please - extreemly stuck watch

1. I need to work out the following simultaneous linear equation:

s=ut+1/2at²

a is constant acceleration, u is initial velocity, t is time

after times of 3 seconds and 4 seconds the distances travelled were 25mtr and 35mtr

determine the value of u and a

2. (Original post by leeroy221)
I need to work out the following simultaneous linear equation:

a is constant acceleration, u is initial velocity, t is time

after times of 3 seconds and 4 seconds the distances travelled were 25mtr and 35mtr

determine the value of u and a

your image didnt come out right

Edit: its fine now
3. (Original post by leeroy221)
I need to work out the following simultaneous linear equation:

s=ut+1/2at²

a is constant acceleration, u is initial velocity, t is time

after times of 3 seconds and 4 seconds the distances travelled were 25mtr

25 = 3u + 1/2 * a * 9

and 35mtr

determine the value of u and a

35 = 4u + 1/2 *a a * 16 = 4u + 8a

That's two equations in two variables. Surely you can do simultaneous equations?
4. (Original post by leeroy221)
x.
So you can form 2 questions from this info;

and

.
.
.

have you got his far?
5. (Original post by Zacken)
[/color][/font][/size]

25 = 3u + 1/2 * a * 9

[size=3][font=Times New Roman][color=#000000]

35 = 4u + 1/2 *a a * 16 = 4u + 8a

That's two equations in two variables. Surely you can do simultaneous equations?
Yes, I need to solve a pair of simultaneous equations. Unfortunatly I missed this section due to time off with an illness. If you could help with workings out it would be appreciated so I can understand it and complete the remaining questions I have.
6. (Original post by leeroy221)
Yes, I need to solve a pair of simultaneous equations. Unfortunatly I missed this section due to time off with an illness. If you could help with workings out it would be appreciated so I can understand it and complete the remaining questions I have.
Dylan did it.
7. (Original post by DylanJ42)
So you can form 2 questions from this info;

and

.
.
.

have you got his far?
Thanks Dylan, so is that the end /answer?
How do I find the values of u and a?
Sorry, this topic is totally new to me
8. (Original post by leeroy221)
Thanks Dylan, so is that the end /answer?
How do I find the values of u and a?
Sorry, this topic is totally new to me
Not quite. From the second equation, we re-arrange to get then plug this into the first equation to get:

which I'm sure you can solve for and then plug it back into to find .
9. (Original post by leeroy221)
Thanks Dylan, so is that the end /answer?
How do I find the values of u and a?
Sorry, this topic is totally new to me
Those last two are basic simultaneous equations, you should be able to solve that
10. (Original post by Asuna Yuuki)
Those last two are basic simultaneous equations, you should be able to solve that
It's clear that he/she can't.
11. (Original post by leeroy221)
Thanks Dylan, so is that the end /answer?
How do I find the values of u and a?
Sorry, this topic is totally new to me
Don't be sorry, its great that you're asking for help

We have two equations in front of us which are;

I will multiply (1) by 2 as its never nice to work with fractions

This next step is very important, we have to remove a variable somehow, we have the choice to remove u or a, in this case it looks easier to remove u so heres what were going to do;

multiply (1) by 2 and multiply (2) by 3 (you'll see why soon). (1) and (2) then become;

Notice we've got the coefficient of u the same. So lets do (you can do (1)-(2) if you wish but it makes everything minus which is boke)

We now have a value of a, so now all thats left to do is find the value of u, so well go back to (1) and (2) and choose one to sub our value of a into (again choose whichever looks easiest.)

Let's choose

so subbing in our value for a we get;

This part is optional; sub your values for u and a into (2) to check if it works

which is correct, so were done

Edit: holy mother of god i spent about 30mins on this... my latex is so slow

Edit II: sorry for full solution btw but i felt OP would benefit more from seeing a worked example rather than small hints, but maybe that's not my decision to make

Edit III; T.I.L. \boxed
12. (Original post by DylanJ42)
Don't be sorry, its great that you're asking for help

We have two equations in front of us which are;

I will multiply (1) by 2 as its never nice to work with fractions

This next step is very important, we have to remove a variable somehow, we have the choice to remove u or a, in this case it looks easier to remove u so heres what were going to do;

multiply (1) by 2 and multiply (2) by 3 (you'll see why soon). (1) and (2) then become;

Notice we've got the coefficient of u the same. So lets do (you can do (1)-(2) if you wish but it makes everything minus which is boke)

We now have a value of a, so now all thats left to do is find the value of u, so well go back to (1) and (2) and choose one to sub our value of a into (again choose whichever looks easiest.)

Let's choose

so subbing in our value for a we get;

This part is optional; sub your values for u and a into (2) to check if it works

which is correct, so were done

Edit: holy mother of god i spent about 30mins on this... my latex is so slow

Edit II: sorry for full solution btw but i felt OP would benefit more from seeing a worked example rather than small hints, but maybe that's not my decision to make

Edit III; T.I.L. \boxed
Dylan, that it brilliant thank you so much.
I understand it until where you get the value of U? How do you get that fraction?
13. (Original post by leeroy221)
Dylan, that it brilliant thank you so much.
I understand it until where you get the value of U? How do you get that fraction?

Oh sorry maybe I done that part too quickly,

so once we get a value of a were going to want to sub it into either (1) or (2) to find our value of u. As I said before (1) looks easier so we'll sub into

so subbing in our value for we get;

(notice how ive just replaced the letter "a" with 5/6)

anddd youre done

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