Edexcel M3 - May 13th, 2015 [Exam discussion thread]

How many marks do you lose for not showing solving of the quadratic even if you get the right answer


Posted from TSR Mobile

I'm sure you wouldn't lose any as long as the answers correct and you've not jumped too many steps

An M1 maybe? Depends on how harsh the mark scheme is.

He did it twice unfortunately. Sad cause he got everything right.


Posted from TSR Mobile

Okay these are my wrong answers, and guesses how many marks I would've lost?
1. b. I got "1cm" for some reason, but I did change in Epe= or where Epe was initially x=0.4 and final x=x and gpe was mgX


4.c my guess for trapezium rule was I figured out t=1 t=2, and x=0 x=7, then I did a table with t=1,1.25,1.5,1.75,2 and v= values for them, then I got 4.17.


6.b. For the SHM I was an idiot and did -12x + 8x = -4x= 0.5Acc so -8x=acc
c. Used then impulse and mass to find v, then did vmax=omega A, but with my wrong omega.
d. Wrong omega and A but x=1.2 for 1.2=AsinWt


7.c I equated the suvats for horizontal distance and vertical distance and found T and rearranged it using T=X/ucos into s=it+1/2gt^2. I got 0.82m which i know is wrong.


Thank you

Okay these are my wrong answers, and guesses how many marks I would've lost?
1. b. I got "1cm" for some reason, but I did change in Epe= or where Epe was initially x=0.4 and final x=x and gpe was mgX


4.c my guess for trapezium rule was I figured out t=1 t=2, and x=0 x=7, then I did a table with t=1,1.25,1.5,1.75,2 and v= values for them, then I got 4.17.


6.b. For the SHM I was an idiot and did -12x + 8x = -4x= 0.5Acc so -8x=acc
c. Used then impulse and mass to find v, then did vmax=omega A, but with my wrong omega.
d. Wrong omega and A but x=1.2 for 1.2=AsinWt


7.c I equated the suvats for horizontal distance and vertical distance and found T and rearranged it using T=X/ucos into s=it+1/2gt^2. I got 0.82m which i know is wrong.


Thank you

How many marks do you lose for not showing solving of the quadratic even if you get the right answer


Posted from TSR Mobile

What did you get for your t in the last one?

Haven't had a chance to read through the thread but these are some quick solutions I've written up based on what I wrote in the exam. Be sure to tell me if I've made a mistake.
Edit: forgot 7c I'll scan that in a minute.

ooops, yeah I can confirm it was a=-40x

Damn, yeah. Oh well.

And I got 1.2 for the last question
Maybe I did **** after all for ****'s sake.. the one time I think it went well..

I know what you did, I did the same. You took the vertical velocity as it leaves the sphere as a positive as if it was being fired up so T (the time before it hits the ground) is longer. Such a rookie mistake I hope it doesn't cost us more than 2 marks

i got same answer for all of them. cheer up buddy.
ANd what did u get for the last 7c.