Seeing as nobody has posted anything yet, I shall share my answers. I can't say I studied much, as quite a lot of guess work was involved. Would appreciate if anyone is willing to provide explanations for the harder qns.
So here it goes:
(1 to 10) CABDD CCBDB
(11 to 20) CBACA BACBD
(21 to 30) DBBDB BDBAC
(31 to 40) DCDBB CADAD
I also put B for Q25, but the answer should be A. *Cry*. Cause they only ask for the direction of the resultant electric field. The magnitude of the electric field is the same at S and Q, P and R, but all are in the same direction. T.T
I didn't take down my answers lol, but I think I still rmb some. Particularly unsure about questions 11 and 32. If you ask me for the other questions I might be able to help haha, though answers might not be correct. And qn25 lol yeah I spent so much time on it only to realise after that they're asking for directions. Oh and for question 12, shouldn't it be a maximum radius instead? I worked it out to be r<=v^2/g. Cos minimum then can be zero what? Lol what are your opinions guys?
Q11 should be B.
Option A is wrong because there's mass and gravitational force that is acting on it.
Option C is wrong because the Mass of the astronaut and the capsule is different, so the force is different.
Option D is wrong because there's gravitational force acting on the astronaut.
I think minimum not zero because if it's zero, it's not considered as curvature already? Not sure about that haha.
How did you get the answer for Q9,16,26?
Originally posted by oayihzeet:Q11 should be B.
Option A is wrong because there's mass and gravitational force that is acting on it.
Option C is wrong because the Mass of the astronaut and the capsule is different, so the force is different.
Option D is wrong because there's gravitational force acting on the astronaut.I think minimum not zero because if it's zero, it's not considered as curvature already? Not sure about that haha.
How did you get the answer for Q9,16,26?
yeah I put B too cos it's the only right answer.. but any idea why it explains the weightlessness?
haha but then still it's r<=v^2/g right? or did I do wrongly hmm
for qn 9 I got 40. first find the engine force at v=10 by F=ma+friction. then find the power using P=Fv. then max v is when F=friction (acceleration is zero).
Qn 16 is just the graph for a less damped oscillation no? which is B
26 I got D, not sure lol though. I thought cos I=Q/t, so it's the charge passing through a point per unit time, which is just charge of electron x frequency? not sure though cos I didn't use the radius :/
hmm my two cents' worth not sure how reliable haha
http://www.physicsclassroom.com/class/circles/Lesson-4/Weightlessness-in-Orbit
I perceive weightlessness as something like no reaction/normal force acting on us. Not sure about how accurate my understanding is. haha
I got my answer as B also, but not too sure about the answer. Quite uncertain about Q12.
Oh, I got the same answer as you for Q9, but my confusion is from the understanding of the word 'constant power'. Constant power can mean constant input power or constant output power? O.o
Q16, What's the difference between option A and B? o.o
Oh, and Q13, why is the answer A? O.o
Originally posted by oayihzeet:http://www.physicsclassroom.com/class/circles/Lesson-4/Weightlessness-in-Orbit
I perceive weightlessness as something like no reaction/normal force acting on us. Not sure about how accurate my understanding is. hahaI got my answer as B also, but not too sure about the answer. Quite uncertain about Q12.
Oh, I got the same answer as you for Q9, but my confusion is from the understanding of the word 'constant power'. Constant power can mean constant input power or constant output power? O.o
Q16, What's the difference between option A and B? o.o
Oh, and Q13, why is the answer A? O.o
Q11. yeaa but why does having the same centripetal acceleration as the capsule mean that contact force is zero? :O
Q9. hahah I think you think too much! they also never say about efficiency so should be constant output power ba..
Q16. A has a different amplitude at f=0, while B the same. correct one is B
huh Q13 is A? haha I put B lol I thought it should be zero at the centre..?
Q16 Oh, I didn't realize the difference between option A and B. Sigh.
Q13, My fault, I thought it was A because both my friend and the creator of this thread put A for the answer. Now that I've relooked at the question again, B makes sense, if only I've realized it during the exams. haha.
As for Q40, the question regarding the mass of the nucleus in the excited state, what we have to do is to convert the energy '2.13x 10^13' into mass and add right? o.o
i want bio paper1 ans～
no one？
For bio, my answers are
thanku
Originally posted by oayihzeet:I think (purely my own interpretation), that because both the astronaut and space capsule is in a circular orbit around the earth, the gravitational force on the astronaut/space capsule is the centripetal force. Having the same centripetal acceleration means that both the astronaut/space capsule is moving around the earth at the same rate?
(I'm don't think I'm making any sense here already. haha.) Sorry about that.Q16 Oh, I didn't realize the difference between option A and B. Sigh.
Q13, My fault, I thought it was A because both my friend and the creator of this thread put A for the answer. Now that I've relooked at the question again, B makes sense, if only I've realized it during the exams. haha.
As for Q40, the question regarding the mass of the nucleus in the excited state, what we have to do is to convert the energy '2.13x 10^13' into mass and add right? o.o
hmm now that you say it it makes sense.. cos for both astronaut and capsule GM/r^2 = v^2/r. but that kinda requires some linking to the conclusion that contact force is zero..
Q16 oh so you chose wrongly? ouch, there there it's okayy
Q13 haha okayy
Q40 yup, there's an exact same question (even the values!) in a past year paper(2007Q40) lol when I saw the question I was like "ok the answer must be C"