xforeverlove21 said:
The thing is this is an introductory physics course (Physics 1) since I am taking it in 2nd year I already did calc I and calc II, I even aced calc II so I'm assuming my math background is pretty strong. Maybe it's the understanding part? Am I supposed to go over several textbooks, lecture notes... before I even attempt questions? Usually I just write the main points and formulas down.
Here, let me give you a few recent examples from my brother who's taking intro E&M:
This first example illustrates not completely understanding the physics (or at least not applying concepts correctly), say you have a charge at the origin of a coordinate system in ##\mathbb{R^2}## of strength Q, and another particle with mass m, charge q, a distance x from Q on the x-axis and an initial velocity of v in the y direction. The problem wants you to find the charge Q so that the other particle q experiences uniform circular motion around Q. So, applying the math,
$$ m\frac{v^2}{x}=\frac{1}{4\pi\epsilon_0}\frac{Qq}{x^2}$$
or,
$$\frac{4\pi\epsilon_0 mv^2x}{q}=Q$$
He plugged in his numbers and solved for Q, but forgot to apply the physics correctly. For this to happen, Q needs to be of an opposite charge with respect to q. In this case he should have used the original numbers given to determine the sign of Q. He goofed on the physics.
An example where he failed to apply math correctly:
Three charges, ##q_1, q_2, q_3## are held at a fixed distance d, with all three charges equidistant from one another. Find the strength of the electric force that acts on ##q_1.## This problem just requires you to use Coulomb's law to find the ##\vec{F}## on each, which he did, plugged in his numbers and got two Forces. The problem came when he was trying to break the force (one or two forces, depending on how you define things) into it's individual components. He had drew things so that one force was only in one direction to simplify things, but the other force needed to be reduced to components to find the total force. He didn't think to apply to apply the law or cosines, or split things up, instead he was trying to force ##F_x=F\cos(60)## and ##F_y=F\sin(60)##. Which is wrong. He had failed to apply the math he already knew.
This is a kid that also has gotten A's in calculus 1,2,3, a B in LA, and is taking a course in ODE's. The majority of the problems I help him with though are of the latter type, he just fails to apply the mathematics correctly. Math he should already know. If this is your kind of problem with physics, rereading the book or lectures or whatever isn't going to help at all, because it's assumed you're bringing this math into physics with you.
If you have a concrete example of what you're struggling with, you should post it in the HW section, so others can help guide you to answer, and maybe point out where your weaknesses are. If you don't even get to either point above, you just need more practice working problems, it's a skill.
Generally, you should always:
Draw a picture.
Write down what concepts of physics apply.
Write down what you want to know.
Write down what you know from the problem.
Apply the correct mathematical model, leaving everything as variables.
When you're able to solve for what you want to know, in terms of what you know, plug in your numbers.
Work the calculation, give answer to correct significance.
Check that it makes sense, analyze the math model you used. What's it telling you, what does it say about the physics?
See if there's another way to work the problem.
Compare it to other problems you've done, was there any uncommonly used tools that helped you with this one compared to others?
Check answer if applicable.
Move on to the next one.
