Common Free-Fall Pitfalls

[@cassieknight6602]

Sometimes it feels as though some teachers don't want us to "get" what they are teaching. What you are doing with your videos is more valuable than you may realize. Understanding the basics properly is critical for more advanced work, and self-esteem.

[@FlippingPhysics]

Thank you for your kind words!

[@Niosvideos]

Amazing, I'm currently a freshman a Purdue univeristy and currently taking physics for the first time, this simple video has helped me way more than any of the TA's or any of the lectures that I have had this semester. Keep the videos up!

[@FlippingPhysics]

Wow. Thank you for such a lovely comment. It's words like these which help to keep me motivated to create my videos. Thanks!

[@haydenlane3101]

Boiler up

[@WeAreShowboat]

Really outstanding. Each video gets better and better!

[@introvideo5064]

Your video editing skills are SUUUUUUUUUUUUUPPPPPPEEEEEEEERRRRRRRRRRRRR! Physics teacher + great visualization = chef's kiss. Much grateful to have founded you.

[@tlczenie4667]

This video helped me so much! It is excellent how you illustrated the hypothetical situations, it makes everything so much clearer

[@lee-em5qw]

i hope you know how your videos helped me pass my physics, sir. truly a blessing!!

[@FlippingPhysics]

Wonderful!

[@kennethmcneil9540]

Hey Mr. P, you should name these topics, "Pitfalls of Free-Fall", I think it just sounds more catchy. I was actually getting questions wrong on my chapter review and this video laid out clearly what I want not understanding. Nice job figuring out the most common miscomseptions. "Pitfalls of Free-Fall", I mean come on it so catchy.

[@FlippingPhysics]

Nah. I like my title. Glad you like the video though.

[@Uncertaintycat]

Great video, Mr. P! One I would love to see but would understandably be difficult to make, is how to form constraints in ill-defined problems so that it becomes solvable. Frequently, my textbook will give a problem, then in the solution, make an assumption or define a constraint that makes it solvable. I am great at math, but not so good at making up constraints, so it is causing me all sorts of aggravation!

[@FlippingPhysics]

Can you give me some specific examples? (I'm not sure what you mean exactly.)

[@Uncertaintycat]

It might be me being too rigid in my thinking or cherry picking or bad luck, but I just had to do a string of rotation problems in Halliday and Resnick's Fundamentals of Physics where every object with a radius was assumed to be a sphere, even though lots of things have radiuses and yet are not spheres. The student's solution manual has tons of stuff like "assume it starts at rest", "Assume level ground", but it isn't given in the problem. I am too used to mathematics, where we declare assumptions at the outset. Maybe it is just this particular textbook, however, as I don't see this popping up in Schaum's outline, but the problems in there are far simpler, too. But this sounds like I am whining, and I am not! I don't mean this is a bad thing! In "the real world," I must place constraints on situations in order to solve problems or create models, and knowing when and how to do this is just not something really covered in any books or videos I have seen. Perhaps too esoteric a discussion, so I apologize for derailing your video :)

[@FlippingPhysics]

"every object with a radius was assumed to be a sphere" sounds like lazy problem writing. "assume it starts at rest" should be clear from the problem statement. "Assume level ground" is pretty consistent with physics problems. If it doesn't say, we assume the ground is level. I don't hear this as whining. This is good and useful feedback. Makes me think about what I assume but don't explicitly state. Have you ever tried Richard White's problems? www.learnapphysics.com (Forgive me if I have mentioned this before.)

[@Uncertaintycat]

Yes you did mention the learnapphysics.com site, it is wonderful! Thank you :)

[@longlostbuilder1856]

Just to be reaaaaally sure I get it, the acceleration in free fall is only negative g because we give it an up and down direction with are either positive or negative, and since it is "falling" it has just that pulling it downward therefore it is negative? Am I right?

[@rithwiqnair537]

Mr.P, When you defined free-fall as " when a body is not touching anything and is in a hypothetical air-less atmosphere" , I'm a little puzzled . What about magnetic levitation ? or levitation of object using sound waves?

[@FlippingPhysics]

Sequentially this video is before I teach about forces, therefore I cannot define free fall in terms of forces. An object is in free fall if the only force acting on it is the force of gravity. Magnetic levitation is caused by a force = not free fall. Levitation using sound waves uses the force of the air to hold up the object (sound is compression and rarifaction of air) = not free fall. Hope that helps!

[@rithwiqnair537]

Thank You!

[@bronzedflames]

thanks for everything, Mr. P! :) this totally cleared up my misconceptions

[@FlippingPhysics]

+bronzedflames That's my job!

[@shahdmalkawi6174]

+Flipping Physics I don't understand... When an object is going faster it actually means it's accelerating.. Would you please clear that up??

[@FlippingPhysics]

Um, i'm not really sure what you are asking, however, try this video to see if you can clear up the difference between velocity and acceleration. It should help. www.flippingphysics.com/understanding-uam.html

[@shahdmalkawi6174]

+Flipping Physics oh well, when you were talking about the two balls that were thrown downwards, you've written "yes it moves faster and no it does not accelerate more".. I meant how come it doesn't accelerate more if it's moving fast?

[@FlippingPhysics]

Acceleration is how quickly the velocity of an object is changing, it is not how fast an object is moving. Giving an object a large initial velocity in projectile motion won't change the acceleration of that object after you let go of it. Please watch the video I referenced, it should really help.

[@rhycemckenziegammad2215]

The only thing that can help me in my physics is You, thank you so much!! 고망워

[@FlippingPhysics]

+Rhyce Mckenzie 천만에요 😀

[@nhunguyenthiquynh9942]

your vid is so good 🎉🎉🎉🎉🎉

[@vivianjoyasimetin429]

Nicely done!

[@georgemathew8218]

Very Good Explanation Sir. @

[@FlippingPhysics]

Thanks. (again)

[@milindbebarta2226]

Wow you make it so fun

[@FlippingPhysics]

Thanks. That is one of my main goals.

[@gravysnake78]

ah yes, the god like figure of Mr. P

[@beastmode3870]

7 year anniversary tomorrow

[@asthatiwari2648]

U r osm man..but plz b a lil slow

[@ka8532]

Honestly I am Billy.

[@FlippingPhysics]

Your honesty is appreciated.