AQA MM2B Friday 6th June

5. P=40.v.v v=50
P=40.2500
P=100,000W
100,000=(1500a + 40x25)25
a=(4000-1000)/1500
a=2

This working is spot on so the answer was 2 not 2.67 i'm sorry to say.

ok, your answer may be correct but it doesnt really help if i dont actually know what your sayin. ie, explain what you're doing. i must have got 4000/1500 rather than your 3000/1500, can you tell me why?

You were given

P = 100000
Resistive force = 40v
Velocity= 25
Mass of van = 1500


using Power = driving force x velocity

Power/velocity = driving force

so 100000 / 25 = driving force = 4000

Using F = ma

driving force - resistance force = ma

so 4000 - 40v = 1500 a
4000 - 40(25) = 1500a
2 = a

hope this helps

answers:

1.differentiate something pretty easy. and find force cant remember answers exavtly.

2. found the 21g think other T was 19g not sure tho.

3. coordinates were (9.3,12.8) may be other way round.

4. max v for last bit was 34.5, a=2

5. well...
could do 1st bit.
showed that displacemnt was 8i at t=0 and t=pi was -8i
therefore a cirlce as pi is half a circle therefore it should be opposite.
s=2
for last bit i put magnitude of a=2 but prob wrong

6.got v and t=ln2/0.05=some number

7.said that for min u T at top=0.
for b) T=5ag

8)a)just integrate
b)e=0.something
found that v^2=something
then x=0.208

i completely missed out the last question. i couldve sworn i saw the 'end of questions' below question 7.

bolllllluxxxx

I thought it was a lot harder than the past papers, then again, I always find it harder than the past papers lol! Looking at the grade boundaries for past papers, it seems to be around 83% for an A, so I still think we'd be looking at around 60/75 for an A.