Physics 3.5.4a - Projectile Practice Problem 1

Practice Problem on Projectile Motion.

[michaelkhalil]

I never write comments so when I do you know I mean this so sincerely. Physics has never ever made sense to me since middle and high school. Now in college I gotta get it so I don't fail these classes. This is the first time I've felt confident and actually understood even slightly what I was doing. So thank you Derek!!

[MovieTrim]

Wow the quality and organization of his calculations as well as pace and verbal description of the problem beats even KHANA. Great quality content I'm subbed

[earlcamblelover]

What about when horizontal distance is not given ??

[sheeraa]

should we just conclude that for horizontal, there is no acceleration? 

[cinechromefilms]

13
years later, this is still helpful. Thank you sir

[josuekoenig]

I watch these because my teacher is bad

[superbaby]

love the fact that its colourful!
helps to clearify things a lot!

[Axualkilla]

dude thank you so much I was having a mental breakdown because of physics but you made it so much more simple

[itsjasminagain]

Thank you! I've been having so much problems understanding this and I have my first exam tomorrow.. This helped so much!

[derekowens]

@Ell4Sh Yes, that approach would also work. There are typically multiple ways to set up a problem, all of which should give the same final answer. I set it up with 0 a the top because all of the motion and the acceleration are downward, in this problem, and setting it up this way makes all the displacement, velocity, and acceleration numbers positive. The other approach is fine, though.

[derekowens]

I typically use v_0 for the initial velocity. That's v with a zero in the subscript position. It basically means "velocity at time zero" or "velocity when t=0". Then I use v by itself for velocity at some later time. Using u works also, though. Good notation definitely helps, but it's not as important as the concept.

[TheOne-spvx]

Why is Y positive when it goes downwards? I always see people making Y positive upwards. Now this made me more confused😔

Your tutoring skills is very good, but there's still a thing which I would like to clarify: when will you know that acceleration due to gravity is positive or negative? In what circumstances?
because every in every Physics class, they will use positive and negative values of acceleration due to gravity. Please help. Thanks in advance.

[princesspat]

Thank you so much Im doing my first year of biomed but i didnt learn much about physics in high school. I know theres projectile formulas but I've been trying to find videos where they use the kinematics one since that increases your understanding. Thank you so much for making these, it was very clear!

[micheleloga]

Absolutely AMAZING! I can't get my Physics teacher to explain any of this to me and my book is too confusing to help me with these kind of problems. Thank you so much for doing this video! I understand it so much more now.

[derekowens]

Yes, that's correct. That's because for a projectile, there is no acceleration horizontally, so the velocity is the same the entire time, and you can find it with the equation x/t.

[derekowens]

@omar3211 Acceleration near the earth's surface, due to gravity, is 9.8 m/s^2 (or very close to that). That's basically a constant (if you're on earth).

[abhisheksaini-lwli]

seriously, i think people like u deserve a great prize... ive physics exam tommorow and i didnt know anything... thanks very much

[derekowens]

At the start of a problem, you need to choose which direction you will call positive. You can call up positive and down negative, or you can call down positive and up negative. Pick one, and just stick with it through the whole problem. If up is positive, then the acceleration due to gravity is negative. If down is the positive direction, then the acceleration due to gravity is positive.

[SBchampsXLII]

Thank you so much for uploading these videos. You explain things so well, and your visuals are amazing.