For question part two of the momentum question when they asked about using he laws, i wrote the sum of momentum before = the sum of momentum after providing no external forces acts on it hence the system will be in equilibrium. Air resistance is acting on the system, hence the whole system is not in equilibrium and the momentum of the air changed.

Is this right?

Reply 185

babyetu

Original post by money-for-all

use the horizontal motion equations.........
not suvat

That implies that the deceleration was 0 horizontally, but it was (-)2.7...

Original post by icecubeinferno

Should be Newton's 3rd law, when object A exerts a force on B, object B exerts and equal and opposite force on A.

Reply 186

jcouchman

Original post by Akashi

Yeah I messed up on using exact values for that question as well as the resistance of the probe question so both answers are off by a bit :/

If you you used exact values you should be fine, on the circuit questions did you get current ad 0.06A for one part and 0.15 ohms for another part?

Reply 187

Liam2020

How do you work out the acceleration? I got it wrong because I got 1.0 ms-2

Reply 188

Symeon123

Guyz I accidently thought that the spots for the microwave question were the unheated parts but i did everything else correctly. how many marks am i likely to lose?

Reply 189

babyetu

Original post by Liam2020

How do you work out the acceleration? I got it wrong because I got 1.0 ms-2

F=ma rearrange to a=F/m but you had to convert the kN to N for force.

Reply 190

JoshFarrell

Does anyone know how many marks it was out of and the average mark needed for an A?

Reply 191

Akashi

Original post by jcouchman

If you you used exact values you should be fine, on the circuit questions did you get current ad 0.06A for one part and 0.15 ohms for another part?

Mhm, that's the thing I used the rounded values I gave in the previous answers :/

Yep I got 0.064 ohms for the current through R3 was it? and I got 0.15 ohms for the resistance of the probe^^

Reply 192

lukearcus

Anyone got an unofficial markscheme yet?

Reply 193

jcouchman

Original post by Akashi

Mhm, that's the thing I used the rounded values I gave in the previous answers :/

Yep I got 0.064 ohms for the current through R3 was it? and I got 0.15 ohms for the resistance of the probe^^

there is usually a bit of leniance with rounded values so you should be fine, I hope there is more mechanics on paper 2 as I'm currently revising mechanics for further maths

Reply 194

jcouchman

Original post by JoshFarrell

Does anyone know how many marks it was out of and the average mark needed for an A?

out of 70 and i would guess around 50ish as it is a new spec and it seems like many people found it difficult

Reply 195

Med3

Was it as hard as the specimen papers?

Reply 196

aipomaniac

Original post by Akashi

Didn't the question only ask as to whether the air exerts a force in the direction of motion?

I interpreted it just as 'see which laws of motion can be applied here' but I am sure either way will be fine :smile:

Reply 197

ShivP_98

For the chocolate, it was 14cm so 0.14m and it was therefore 3x10^8 / 0.14 ?

Reply 198

Liam2020

Original post by babyetu

F=ma rearrange to a=F/m but you had to convert the kN to N for force.

yeah i know now. its because i did 119000-190000 = ma but you were supposed to do 190000 = ma

Reply 199

matrix37

Original post by money-for-all

1700m (2.s.f) distance travelled by plane, anyone ?

if there was force going forward so F-R=ma then 1700 m is correct.
but if the only force acting was the resistive force then 851m is the right answer.
I wasn't sure if there were any forces acting forward since the question said the air was travelling the same as in part ii