ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: NeedHelpWithStudy on April 17, 2014, 10:42:05 am
-
Hello guys well i have to do my physics motion sac on next wednesday and i'm a bit nervous. Has any of you done it? if so how was it? Was t really difficult? Apparently our sac is going to be really hard ( around 9 pages long) and he also said there is another school which also did our sac so yeah. Please reply me thank you.
-
Hey
Our motion sac comprised of chapters 1-3 so there was a large component on gravitation as well. But the motion part wasn't too difficult, as we only had questions on momentum, hooke's law and projectiles. Normally, most sacs are 1 mark a minute so organise your time accordingly.
Good Luck :D
-
Hello guys well i have to do my physics motion sac on next wednesday and i'm a bit nervous. Has any of you done it? if so how was it? Was t really difficult? Apparently our sac is going to be really hard ( around 9 pages long) and he also said there is another school which also did our sac so yeah. Please reply me thank you.
Hey I just did my physics Sac yesterday and I had no trouble answering any of the Q as they are mostly similar to the checkpoints i bought (did most of them). For my Sac There was a lot of emphasis on the topic Gravity, circular motion and projectiles, but nothing too difficult, as long as you wrote your formulas on the cheet sheet you should be fine. You should know the difference between weightlessness and apparent weightlessness and be able to give an example for each. So if you do all of the topics from the physics checkpoints and checking your answers, you should have no problems with your sac.
-
Although I did an extended practical report on motion, There are some tips that I can provide which I found noteworthy (btw, I will be using some common abbreviations and symbols):
- In a-t graph, when u=0, the area under graph gives velocity at time t.
- When a ball bounces on a floor and at the very moment that it is at full compression, in spite of being stationery, It has a acting upward. Thereby, N>W.
- A bicycle with no brake going down an inclined road will eventually have constant v. this is coz as the speed increases, air fric increases. Eventually, they will be equal in size and we will have inertia.
- generally there is three types of frictions acting on objects with tyres:1) rolling friction(opposing), 2) static fric(aka driving F, supporting), 3) Air resistance(opposing)
- W=Fx, is not applicable to springs as constant force is not applied to it when it stretches/compresses (tbh, I am sometimes in doubt with this one)
- In projectile motion, say in a symmetric projection where the object launches and lands on the same horizontal level, I used to divide the motion in half, find the time from launch to highest point, then times it by 2. But I have realised that since the a is constant at all times, we can just find the total t in one step. (I am not sure about others, but I found it as a big discovery lol)
- There is a formula for when a projectile motion is symmetrical(again), which we can use to find the range directly. I havent seen it on the text books: Range=(v^2sin(2theta))/g where 'theta' is the angle of launch
- In projectile motion, velocity is always min. at max height (a bit obvious)
- In circular motion, applying too much force will exceed the max driving fric possible. As such the car would skid out of its circular path.
- Another way of referring to the direction of the motion of the object in circular motion is to say "radially inwards".
- In circular motion on banked surface, if v>design speed, the car will travel up the track. Driver will have to turn slightly down to create fric towards bottom of the track, in order to maintain its speed at design speed.
- greatest range of an object in projectile motion is when it is projected at 45 degrees to horizontal.
Good luck with ur sac :)
EDIT: By the way, is the poll in this thread created inadvertently?