Trouble with mechanics. Is Physics right for me?

[astr0]

I am a undergrad physics major taking my first calculus bases physics course. I am having trouble with Mechanics, which is a main topic of this course. I understand the basic equations, but I find that the problems we are given for homework and on tests involve finding different and combined forms of these equations. These different forms are not covered in class, and there aren't relevant examples in the textbook. I really love physics, and have been fascinated with the topic for as long as I can remember, but if I am having trouble with mechanics, is physics really for me? Do I need to be very good at mechanics to excel in my upcoming physics courses?

 

[fss]

If you expect to have every formula handed to you, physics is most definitely not for you.

 

[clope023]

I am a undergrad physics major taking my first calculus bases physics course. I am having trouble with Mechanics, which is a main topic of this course. I understand the basic equations, but I find that the problems we are given for homework and on tests involve finding different and combined forms of these equations. These different forms are not covered in class, and there aren't relevant examples in the textbook. I really love physics, and have been fascinated with the topic for as long as I can remember, but if I am having trouble with mechanics, is physics really for me? Do I need to be very good at mechanics to excel in my upcoming physics courses?

Get another textbook (I suggest Schaum's outlines) and learn to like deriving your own solutions.

 

[nlsherrill]

I am a undergrad physics major taking my first calculus bases physics course. I am having trouble with Mechanics, which is a main topic of this course. I understand the basic equations, but I find that the problems we are given for homework and on tests involve finding different and combined forms of these equations. These different forms are not covered in class, and there aren't relevant examples in the textbook. I really love physics, and have been fascinated with the topic for as long as I can remember, but if I am having trouble with mechanics, is physics really for me? Do I need to be very good at mechanics to excel in my upcoming physics courses?

The equations presented in the text are usually just a "guide" to problem solving. Really what you do in this course is learn how to solve physics problems. Frequently you are going to have to come up with your own systems of equations based on known laws. And for mechanics, its almost aways Newton's Second Law.

Not doing well in this course will not be the end of the world. I know someone who essentially failed his first calc based physics course and now is back making good grades after working at it and getting used to how to approach these problems. A physics problem is kind of like a puzzle. You have to figure out what's going on, then think of a sequential set of steps to set up your equations, then solve and see if it works. It takes time and patience. The only way to really get good at it is lots of practice. Go beyond what the professors asks you to do for homework. Attempt to solve the hardest problems in the book that have solutions somewhere to see if you are right.

 

[astr0]

My biggest obstacle is that I have no one that I can ask questions about problems that I am having trouble with. The professor doesn't care about the students, and there is no physics tutoring at the university I attend. When I get stuck I just get frustrated.

 

[Ivan92]

Doesn't your professor have some office hours? See him/her there.

Also, this is the Physics Forums at your service. :) If you have problem with homework, post up a thread in the Physics part of the forum. There is no guarantee that people will answer right away so just put it up with plenty of time before its due.

 

[astr0]

My professor does have office hours, and he is infamous for turning students away. His reply to questions is usually along the lines of, "I'm sure you'll figure it out if you think about it more." He doesn't offer help, and usually doesn't look away from his computer screen while talking.

 

[AlephZero]

I think your problem is that you want to solve the questions using "standard formulas" - the same way as you might have solved questions about projectiles for example.

Mechanics (and most of the rest of phyiscs) doesn't work like that. What you have to do is apply general principles like Newton's laws of motion, conservation of energy, etc, to make some equations in your unknown variables, and then solve the equations.

When you are studying solved problems, don't try to memorize the equations. Try to see how the equations were derived. Focus on things like drawing free body diagrams, resolving forces and moments, writing expressions for strain and kinetic energy, etc. You want to get to the point where you can look at a problem and say "OK, I have these 3 unknown quantities, and I can set up 3 equations by doing this, this, and this." When you have made a plan like that, you have "solved" the problem so far as the physics is concerned. The rest of the work is just algebra.

 

[lisab]

My professor does have office hours, and he is infamous for turning students away. His reply to questions is usually along the lines of, "I'm sure you'll figure it out if you think about it more." He doesn't offer help, and usually doesn't look away from his computer screen while talking.

That's just rude! Are there TAs available?

 

[astr0]

That's just rude! Are there TAs available?

Our class doesn't have a TA, the professor does all of the grading.

 

[Jack21222]

I'm a physics tutor at my university, and I am running into many students like you who can't seem to make the jump from a general principle to a method to solve a problem. So, you're not alone.

When I first took the first physics class, the way I learned to solve problems was to write down everything you know about the system, writing down all of the unknowns, and then finally writing down the laws of physics that relate those quantities.

Like AlephZero says, the rest is just algebra.

 

[DrummingAtom]

I third the writing down a list of knowns and unknowns. Practice makes perfect and if you get stuck there's always the homework help section of physicforums. Good luck.

 

[G01]

The advice you have been given here is good advice.

If anything, what you need to get out of this mechanics course, is to learn how to solve physics problems.

Your homework and test problems sound normal. Very few physics problems involve cookie cutter equations given in the text. I agree with the above posters. You need to practice deriving the needed equations from the first principles (Newton's Laws, Conservation of Energy, etc.). This is an important skill needed when solving physics problems at all levels, and the one that seems to be the source of your trouble.