AQA June 2011 Mechanics 1B 26th May

I swear in the helicopter question it sed that the helicopter had stopped accelerating?

The angle from which it hits the floor isnt dependent on the height or the distance it travelled i believe, instead its the two velocity components at the time it hits the floor which dictates its direction and hence the angle at which it hits the floor.

Heli didnt change acceleration at all.


Would you not need height to work out the final velocity?

I am positive that the height was 78.4 m (0.5 x 16 x 9.8)
For the tension and the pully you have 5g - T = 5a and T-3g = 3a and as a was 2.45 that means that T is equal to 36.75 N...... i think i am right and not forgetting anything here.
For the projectile question, It hits the floor at an angle of 8.11 degrees from horizontal and as said by someone before, to find the the helicopter time you find the manitude of the acceleration and then substitute into r=ut+0.5at^2 knowing that r/s = 500.
For the last page you found two expressions in terms of P using the horizontal and vertical componants and then solve them silumtaneously by adding the two together to get an epression in terms of 2P and then divide by 2 to get it to 125 something.

Sorry, I was being stupid xD forgot they gave us the time. Well the angle was worth more marks anyway

You got almost all the same as me except the tension, which i think i screwed up, but i got 8.91 not 8.11 for the degrees? was that a typo?

Hey guys, can any of you recall what you got for the bearing in the helicopter question, I got 36.9 degrees, did anyone get the same ... also the angle on the projectiles question, i got 8.9 ... So worried i lost the marks, want to see if its correct .. thanks

Hey guys, can any of you recall what you got for the bearing in the helicopter question, I got 36.9 degrees, did anyone get the same ... also the angle on the projectiles question, i got 8.9 ... So worried i lost the marks, want to see if its correct .. thanks

Bearing, so 037 degrees...

For finding the tension in the string, with the two weights, did everyone get T=3g+5g=78.4N? im starting to think i may have messed up on that one, but its worth only 2 marks so not to bothered if i did.

The bearing was 053 and 36.7 degrees was the angle between the horizontal and the direction so you then needed to minus it from 90..... i think.

I'm pretty sure I got 78.4N for the tension too.

Ok Guys, here are my answers, i got bored during the exam cos i finished so i wrote my answers on some paper and kept it to put up here:
i just wrote answers to the questions, cant remember which sub question goes with which answer so soz but yh..

1) 0.2, 3, 8000
2) 39.2, 11.76, 4.56
3) 400, 64, 26.1
4) m = 9, v = 63 (i forgot to divide it by 9 lol so v is actually 7 )
5)2.45, 36.75, string is light & inextensible, 0.4, 0.98
6) 250, 78.4, 39.2, 253, 8.91 (degrees)
7) 10i+7.5j, 053 (degrees), 40
8) 1.73

i wanna say feel free to criticise if i got stuff wrong, but dont like.. destroy me with criticism