BO__einG From Canada, joined Apr 2000, 2771 posts, RR: 18 Posted (13 years 3 months 1 day 22 hours ago) and read 1044 times:

I have a semester final exam coming up for those two classes.

The exam will be the ultimate final exam which summarizes everything I have learned since September when School started.
I have two guide books and the textbooks and notes I use to help me review the material.. WELL most of the stuff. I need some help with some of the material!! :-(

My trouble is that, I am having trouble with some of the concepts in Physics.
I am also currently doing Physics Grade 11 level.
The stuff I am having trouble are the first 2-3 units I have learned way back in September and October which I now forgot most of the stuff.
I was wondering if any of you guys can offer some help?
If one of you forum guys happen to know a bit about Physics Could I get a little help please?
This test if worth 30% of my overall mark and I am trying my absolute best to ace it so I can go on..

I also tried to look for websites which have information about Physics and include things like questions solutions and information about concepts and formulas.
I used but was unsuccessful.
If any of you know of a good physics or Chemistry site may I get the address please? I am currently trying to look for a site to help me study.

If any of you happen to be a teacher who teaches Physics or like have good knowlege on this, I would MOST like to ask for your assistance on some of the materials.

Kinematics, Dynamics, Planetary Mechanics are the oens Im having most trouble remembering.
For Kinematics- finsing displacement for multi-vectors
and vertical incline projectiles..

Dynamics. well Multi-Vectors with Friction

IIf any of you can offer to give me some assistance with Chemistry I shall be greatly appreciated as well, but I find Physics paramount at this time..

Galilee From , joined Dec 1969, posts, RR:
Reply 1, posted (13 years 3 months 1 day 21 hours ago) and read 1025 times:

When are these exams of your's taking place? It sounds like you have procratinated way too long. Might I suggest that when you don't understand something to ask your teacher right away! The problem is that the subjects of Physics and Chemistry build upon the very first things you learn. If you don't understand the fundamentals, then how can you possibly understand the rest. If you understand everything else then you probably do understand the fundamentals, and don't realize it. Try not to think about it to hard and read you textbooks! I know that when I am having trouble with a particular formula, I am usually just looking into it to deep, instead of just letting flow.
I really don't remember to much from physics, in particular those questions that you have, so I am sorry I cannot be of more help. But from the sounds of it, even if I did know something more than what's in your textbooks, I have a feeling you would not have the time to make any sense of anyway.

PanAm747 From United States of America, joined Feb 2004, 4242 posts, RR: 8
Reply 3, posted (13 years 3 months 1 day 9 hours ago) and read 1002 times:

Kinematics, Dynamics, Planetary Mechanics are the oens Im having most trouble remembering.
For Kinematics- finsing displacement for multi-vectors
and vertical incline projectiles..

Dynamics. well Multi-Vectors with Friction

Looks like you are having trouble with trigonometry and vector addition and subtraction.

For friction forces you just have to remeber they are the same equations as non-friction forces with a coefficient of friction multiplied into it.

For example:

If you have a box siting on the floor the normal force will be:

N = (coffecient of friction "mu")*mass*gravity

If you need help on specific stuff just post it

Pan Am:The World's Most Experienced Airline - P(oor) S(ailor's) A(irline): San Diego's Hometown Airline-Catch Our Smile!

BO__einG From Canada, joined Apr 2000, 2771 posts, RR: 18
Reply 4, posted (13 years 3 months 1 day 7 hours ago) and read 997 times:

Well I actually started reviewing sometime last week.. The Exam for physics is on tuesday the 22 while chemistry is on thursday.
Physics was originaly was supposed to be next friday but was bumped up by 4 days. :-(
Here is one example.

This is for Kinematics:

How far can a quarterback throw a football if he launches the ball with a Velocity of 21.21m/s [West, 38.10 degrees above horizontal)?

Dynamics:

Determine NET FORCE acting on a post if two cables are pulling horizontaly on it Cable A is 350N [E] and cable B is 460N [135degrees].

Those two are my largest problems.
The other units such as Planetary mechanics and Waves arent so hard except possibly a few of those advanced questions while Light unit is a breeze.

BO__einG From Canada, joined Apr 2000, 2771 posts, RR: 18
Reply 5, posted (13 years 3 months 1 day 7 hours ago) and read 992 times:

"Determine NET FORCE acting on a post if two cables are pulling horizontaly on it Cable A is 350N [E] and cable B is 460N [135degrees]."

Dont bother helping me with this one.
I got the answer. Net Force=749.2N and 115.71 degrees.
I separated the 460N at 135degrees to find the N for the East and South vectors. I also subbed 135 by 90 to get 45 degrees to use for get my cosine/sin values for my 2 vectors, turned out to be 325N each.
I then added the East 325N by the first value 350N [E] get 675N[E}
I drew a new disgram and did c2=a2+b2 to get 749.2N
And then for my vector I did the tangent formula of opp/adj to get my answer of 115.71

PanAm747 From United States of America, joined Feb 2004, 4242 posts, RR: 8
Reply 6, posted (13 years 3 months 1 day 6 hours ago) and read 985 times:

The kinematics question is solved by trigonomtry, I can't really say right now, I think you have to find out how much velocity is in the x-direction and how long the ball stays in the air.

I'll check something and get back.

Pan Am:The World's Most Experienced Airline - P(oor) S(ailor's) A(irline): San Diego's Hometown Airline-Catch Our Smile!

Delta-flyer From United States of America, joined Jul 2001, 2676 posts, RR: 6
Reply 7, posted (13 years 3 months 1 day 6 hours ago) and read 982 times:

You start with the kinematic problem in a similar fashion.

Obtain the horizontal and vertical components of the initial ball velocity (vector).

How long will the ball stay in the air? Once released, it rises, reaches a maximum altitude, then falls, all the while maintaining its horizontal velocity (assuming no air resistance).The only force acting on the ball is gravity, which causes an accelaration downward on 9.8 m/s2 (s2 = seconds squared).

The time to reach max. altitude is = {initial vertical velocity} / {acceleration} = 21.21*sin(38.1) / 9.8

The time from max. altitude to fall back down and hit the ground is also the same as above -- so the total time in the air is 2 * 21.21 * sin(38.1) / 9.8 seconds.

Now, how far does the ball travel horizontally in that time?

Horizontal distance = {Horizontal velocity} * time = 21.21*cos(38.1)*2*21.21*sin(38.1)/9.8

You need to understand this, then write it down in your own words, and calculate the answer. Let me know what you get so I can check it.