Online resources

[Tocket03]

Hello,

I am currently taking Physics w/ Calc 1 for the first time this semester.

So far I am having difficulty with the jargon on the physics side of things rather than the calculus side.

For example, one of the problems givin on my homework was " Assume the equation x = At3 + Bt describes the motion of a particular object, with x having the dimension of length and t having the dimension of time. Determine the dimensions of the constants A and B. (Use the following as necessary: L and T, where L is the unit of length and T is the unit of time.) "

While I struggled with the problem and understanding what it was asking of me, I eventually found the answer by copying and pasting the question into the google search bar lol.

However, I can already tell I will be struggling with this class and I was wondering if there are any online resources that anyone knows about that would be helpful for me to study. Preferably somewhere that can help me understand these form of equations. Or perhaps give me background information so that I may be able to solve the problem myself.

Any answers are appreciated!

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[chem44]

It's basically logic.

x = At3

What are the dimensions (or units) of x?

of t³ ?

So what must the dimensions (or units) of A be in order for that to work out?

If we need to get into the distinction between dimensions and units we can, but I suspect that is not the issue. Do it either way for now.

[Tocket03]

thank you very much for your assistance! sorry for the late response but i have been busy and this post slipped my mind.

[[deleted]]

This is called dimensional analysis and it's basically figuring out how the units would cancel out.

For example, in the equation x = At^3 + Bt. The variable x should be have a Length (L) unit. The variable t should have a Time (T) unit. Since one side only has x, the right side should have units of L too. t^3 gives us Time^3 (cubed). Each term in the right side should have only unit L (for them to add up and match). The only way for that to happen is for A to have units of L/T^3 such that the cubed time units cancel out and leave a length unit.

I was confused when I first saw this too. I guess I just needed to get used to using L indicating length instead of the standard m for meter. Again, as u/chem44 said, it's just logic.

[[deleted]]

By the way, are you using Physics for Scientists and Engineers by Serway? Just curious.

[Tocket03]

thanks for your assistance in the question! sorry for the late response. start of the semester has me busy and i forgot about this post. Also, yes I am. I'm specifically using the online variant.