ATTN: any maths boffin

[Chartsy]

a car travel past three points on a road,A,B,C with uniform acceleration....
with AB=80M,BC=60M, and the time taken from a to b= 4s, and the time from b to c=2s, find the acceleration and velocity at point A.

tried the SUVAT approach but can't actually make any of the equations

 

[Chartsy]

i THINK i've found a way to get the acceleration as
80/4=20m/s
60/2=30m/s
thats 10m/s extra in 2 seconds so surely 5/ms acceleration?
then how do get the velocity?

 

[arabianights]

hint: distance travelled is area underneath speed/time graph, and said graph has a constant gradient due to constant acceleration, which makes it a triangle

so draw them out then should be easy

 

[Chartsy]

right, gimme a min as i havent drew one of these out in a while

 

[Chartsy]

dont have square paper on hand, but apparently ...approx 0.8 ?!??!

 

[Chartsy]

well, (from right to left) ive got a constant slope right down into the y axis where it hits 0.8m which is obvs where 0 is ....and 0 is at point A....?

 

[Chartsy]

o wait, wtf am i doing ...hold on

 

[Chartsy]

i just drew a distance time graph

 

[Chartsy]

hint: distance travelled is area underneath speed/time graph, and said graph has a constant gradient due to constant acceleration, which makes it a triangle

so draw them out then should be easy

i have no speed values to make a graph?!

 

[arabianights]

I would complain about your maths teachers lad

 

[Chartsy]

thats true, i had one last 2 years who couldnt handle the class so had to teach myself 'maths'....

 

[Chartsy]

yeh my speed values are 20 and 30 just needa get a pencil

 

[Chartsy]

hint: distance travelled is area underneath speed/time graph, and said graph has a constant gradient due to constant acceleration, which makes it a triangle

so draw them out then should be easy

nah turned out we had to do a simultaneous equation

 

[arabianights]

nah turned out we had to do a simultaneous equation

It's clear from this you don't actually understand the maths.

I don't blame you for this*. I blame the education system.

Simulataneous equation approach is mathematically equivilant to the approach I suggested.

*I may blame you for your arrogance. I'm not sure yet. It may just be a survival technique stemming from growing up in the ****tiest part of the UK. Maybe it hormones. I dunno.

p.s. You're bringing out the worst in me. It almost certainly not your fault and almost certainly a massive defect of mine, but some of the stuff I'm doing is practically bullying, and it's ridiculous I should be doing that to a teenager. It reflects far more badly on me than it does on you, but I have to put you on ignore now to stop it for both our sakes.

Take this as a full and sincere apology in the unlikely event I've caused you any kind of issue.

 

[Chartsy]

never caused any pain dude, sorry that i was :/

 

[Shakone]

This is covered in A-level maths (or used to be when I was doing it). You can get a book on this and learn it (usually the subtopic of mechanics). Someone could solve this for you. But I really hope nobody does. Because
1) This isn't a maths classroom
2) You're lazy
3) It would take away the achievement of you working it out yourself and actually learning something.

You seem to ask question after question, and 90% of them are asked without you at first trying to engage your brain to find the answer yourself.

Maths problem. Where does that hint you should go for a solution? Trading website or maths book? Go learn if you want the answer. At least bloody try.

 

[Chartsy]

This is covered in A-level maths (or used to be when I was doing it). You can get a book on this and learn it (usually the subtopic of mechanics). Someone could solve this for you. But I really hope nobody does. Because
1) This isn't a maths classroom
2) You're lazy
3) It would take away the achievement of you working it out yourself and actually learning something.

You seem to ask question after question, and 90% of them are asked without you at first trying to engage your brain to find the answer yourself.

Maths problem. Where does that hint you should go for a solution? Trading website or maths book? Go learn if you want the answer. At least bloody try.

i did try, don't tell me that i'm lazy when it comes to schoolwork,lol.what i should say is that this is the last question of 20, i've done the other 19 myself and got them all right.
reason i asked because the method i was taught (SUVAT) couldn't answer the question, i thought might as well ask the sharp traders here. i've spent the last week figuring out a lot of maths things, im very independent when it comes to studying so don't try tell me otherwise.

 

[MrGecko]

what do you mean, "SUVAT" didn't work? Doubt you did in in Hamiltonian or whatever, aand it sure isn't quantum mechanics.

 

[Chartsy]

well, SUVAT i meant as in , the method we were taught, which is just to write those letters down and form equations with what we get, but we've never really been taught that , for example the simulataneous equation approach is the same as using a distance/velocity/time graph

 

[Shakone]

How about

Initial Speed = 40/3
Acceleration = 10/3