(New) AP Physics 1 - Unit 2a Review - Newton's Laws and Forces - Exam Prep

[@FlippingPhysics]

Please realize this is a _review_ video. If you are looking for specific, detailed topic videos and problem solution videos, fear not, I have plenty available for you at: www.flippingphysics.com/ap-physics-1.html#newton

[@John-w1h7o]

This is great timing! I've been reviewing kinematics for a while and was wondering today whether to jump into Unit 2 of AP Physics 1 for the first time. Thank you so much for providing these free videos for everyone! I will definitely be buying the ultimate review packet later on in the year.

[@christopherbecke4274]

16:55 I wish this was stated that it takes more force to start an object sliding than to keep it sliding. Because that emphasizes the sliding part as opposed to, say, rolling. (it also has s for start for static and k for keep and kinetic)

[@FlippingPhysics]

Nice. I love this. I agree. This is how I have always stated this, however, you are correct. I will update my verbiage in the future, however, it is not worth the time it would take to change this. Thanks!

[@christopherbecke4274]

20:35 Any way to remember cosine versus sine? I had a student note "slide, sine". Because looking at the diagram, force gravity parallel is opposite the incline angle, so may be confused with sine

[@FlippingPhysics]

Not going to add that in this review video.

[@julielangenbrunner9212]

I would love to see the full gravitational force triangle here (with both legs and the hypotenuse), which would help to justify the sine vs. cosine. Maybe not on either diagram but over to the side? not sure it's worth it to add it.

[@FlippingPhysics]

But then I would feel _inclined_ to explain how the incline angle and the angle in the triangle for the force of gravity components are the same. This is a review video. I cannot include everything. I have an entire video dedicated to those components. www.flippingphysics.com/incline-components.html I think I am not going to include it here.

[@julielangenbrunner9212]

Love the video of you in the turning car. Gives me Drs. Hume and Ivey vibes!

[@FlippingPhysics]

Love that!

[@christopherbecke4274]

2:52 "right in its center". Not sure if the indicator on the surface of the 3-dimensional block of wood is precise enough. If you had time, it would be nice to have a wireframe representation to show that the center is actually inside and not on the surface somewhere

[@FlippingPhysics]

Yeah, I do not think I am going to get into the 3D aspects of this. AP Physics 1 only concerns itself with 1D center of mass anyway...

[@christopherbecke4274]

4:44 "I'm sure there are others" like centripetal force, which should never be on a FBD (or actually any net force)

[@FlippingPhysics]

Yeah, we talked about this in the script phase. Adding centripetal force to this list would imply to me that it is a force like all the others when it is actually just a net force. So, I'm not adding it to the list. Though I am not going to get into fisticuffs about it.

[@christopherbecke4274]

5:16 Should the diagram include something that is applying the applied force? Like a hand or something? And if you argue that you're only drawing the object in the FBD, you've also drawn the surface (although maybe not necessary once you show the hand later)

[@FlippingPhysics]

As you pointed out, I show the hand later. Though I would not consider it wrong to include the hand in the illustration.

[@christopherbecke4274]

4:54 "all forces start at the center of mass" unless you're in the rotation unit

[@FlippingPhysics]

Technically, in a free body diagram all forces start at the center of mass and in a force diagram forces start from the location where they act on the object. Again, that's not for this unit.

[@Favcoder]

Can undo ap physics c mech? Unit 2 everything.

[@FrosteR-y5d]

Where can I get that URP for ap physics 1 im struggling in this class 🙏🏽

[@FlippingPhysics]

You can get the URP for AP Physics 1 here: www.ultimatereviewpacket.com/courses/ap-physics-1 But I would also make sure you make use of every video I have here as well and those are all free: www.flippingphysics.com/ap-physics-1.html

[@julielangenbrunner9212]

The new B's do a great job here too!

[@FlippingPhysics]

I totally agree. Well done by all.

[@christopherbecke4274]

2:29 You say "constant density" while the text says "uniform density". Not exactly the same, but probably close enough to not matter.

[@FlippingPhysics]

Julie is going to definitely flag that one. I probably should have said "uniform density", however, I'm fine with the way it is.

[@julielangenbrunner9212]

@@FlippingPhysics Yup, uniform vs. constant one of my "pecadillos"! Also dimension vs. direction, and probably a dozen others too. But the students never appreciate the differences anyway!

[@juliandominguez4866]

Hello, just a quick question, would I be able to purchase the ultimate Ap physics study guide with a vanilla card?

[@noble554]

Should be able to. I just used a Vanilla card for an online purchase (comedy show tickets for a gift)

[@lightingstrikes8131]

Flipping physics, is it possible to purchase the study guide at a discount?

[@FlippingPhysics]

Unfortunately, no. I give away so much of my content for free that I cannot afford to give discounts on the Ultimate Review Packet.

[@julielangenbrunner9212]

Love all the bananas!

[@julielangenbrunner9212]

And the happy face made from the objects including the banana.

[@FlippingPhysics]

That was a happy accident while I was editing. They weren't quite organized like that and then I was like ... wait a second, I can make a happy face!!

[@julielangenbrunner9212]

In the simple FBD of the Diction(ary), when you're talking about the 3rd law pairs (kzbin.info/www/bejne/qaqtZ3Wjotaonpo), I think it would be better to have the arrows definitely on different objects. In the gravitational force one, you do that, but in all the others the arrows are starting from the same place. Since those aren't FBDs, why not move the start of each arrow so that it's more clearly on the object that it's actually on?

[@FlippingPhysics]

I had already put some thought into this and considered doing it the way you describe, however, these are contact forces and it was important to me to have the forces start at the point of contact. If I move the start of each arrow as you describe, then the forces would no longer be starting at the point of contact. I see both options as having positives and negatives, however, I think I prefer the way I have done it here. The reason I can have the gravitational force arrow separated is because those are field forces.

[@christopherbecke4274]

And I know I'm nit picky in my comments, but I suspect that's what you may be looking for, even if you ignore them all! No worries there.

[@FlippingPhysics]

Yes, all very nit picky, however, those are the best points. So many of the important fixes are very subtle word choices which end up making a big difference. In the end I am not making any changes based on your suggestions, however, thank you so much for taking the time to look through the video!!

[@julielangenbrunner9212]

You're in good company! With me, I mean. :)

[@mowbimpson1653]

$27 to sell to high schoolers is criminal

[@FlippingPhysics]

You are certainly welcome to have your opinion. What are your thoughts on my roughly 40 hours of KZbin videos covering all the AP Physics 1 concepts along with lecture notes to go along with those videos all of which are free and available on my website? For reference, they are located here: www.flippingphysics.com/ap-physics-1.html