This is correct. At 1:06, he states V_i= 20 m/s. Final velocity should be 35.80 or 36 m/s when rounded to significant digits after using the correct initial velocity of 20 m/s.
sir, you could have solved the problem faster if you divided Vi into Vix and Viy. from Viy you could have solved for time(2Viy/g+kinematic equation for distance) and then plug in the time value to get Vfx (which is the same) and Vfy from one of the kinematic equations . Anyway, your videos are really great .
Sir please take a look: A projectile is thrown from ground with velocity 8 m/s. When it is moving with 6 m/s, it is at maximum separation from the point of projection corresponding to the speed 6 m/s. Then this maximum separation corresponding to speed 6 m/s is k meter. Find the value of k
There's something in the equation I don't get... Vfinal=sqrt(Vinitial^2+2gh) >> Vfinal=sqrt(30^2+(9.8)(45)). Why was Vinitial substituted by 30? Wasn't it supposed to be 20 m/s? Thanks for clarifying.
I'm still trying to rationalise this situation, is he behind the glass and if yes how is he able to write and draw with such pinpoint accuracy?🤐🇿🇦🙆🏽♂️
Professor Anderson. Thank you for the wonderful lectures. I comprehend them completely but I couldn't completely understand a part of it i.e. why is Vyf the same as Vyi in the example that you gave us to understand the concept. I concur with you for Vxi=Vi=Vxf as there is no specific acceleration provided that we ignore the air resistance but in the y coordinate the object does undergo an acceleration due to gravitational force while moving downwards.
Correct. If the question is just about final speed, the initial launch angle is irrelevant. However, if you asked a different question, such as how long is it in the air, then the initial launch angle does come into play. Thanks for the question. Cheers, Dr. A
Hello Dr, when do we ignore the negative sign of gravity when calculating? I noticed when you substituted the values while getting the square root of Vi^2+2gh that gravity is written as 9.8 and not -9.8. I get that it's so we don't get an error when calculating because it's a square root, but what's the concept behind this? I hope someone answers. TIA!
hey that's because h is also negative due to the nature of displacement. it will turn out to be positive when multiplied with negative g. sorry i just realized i'm seven months late but i'll comment for the heck of reinforcing it in my head
Hello teacher. How can I find the shooting angle of a ball to hit a basketball hoop, if I have the speed, gravitational acceleration and vertical and horizontal distances? I can't deduce an equation to find the angle when the target is above the launch point.
KIPNGETICH KELVIN, Thanks for the comment, and keep up with the physics! You might also like my new website: www.universityphysics.education Cheers, Dr. A
You can either "throw" a ball up OR "let" it fall down, but you can't do em together. I hope you understand the HUGE difference between the two. If you do, your doubt will get cleared, BTW your statement is wrong!
I calculated the time to be t=1.45 s but negative. Could you clarify how I may have accidentally obtained a negative? Thank you. I used the kinematic equation without acceleration: y=yinitial + 1/2(Vinitial + Vfinal)t
sagar kadam, Not writing backwards (I'm not that talented). The board is called Learning Glass. You can check it out at www.learning.glass Cheers, Dr. A
Adrian Chaix, Yes of course. Thanks for the comment, and keep up with the physics! You might also like my new website: www.universityphysics.education Cheers, Dr. A
Nitin Nitin Dude, The acceleration in X-axis is zero on earth The gravity is pull us back only in y-axis It would be crazy if it's pull us forward hahaha
glorymanheretosleep, Not sure if I did. Seems like I must have done that somewhere. Thanks for the comment, and keep up with the physics! You might also like my new website: www.universityphysics.education Cheers, Dr. A
His skills with writing equations backward is mind boggling.
If only those were actual skills and not just a simple trick. See www.learning.glass
Cheers,
Dr. A
Omg I thought you just mirrored the vid 😱
The advantage he's left handed
He's not writing backwards😂🤣🤣 it's the software
I think the vids just fliped
By the way he did an input mistake. He said that he will take Vi as 20 m/s but he used 30 m/s instead
This is correct. At 1:06, he states V_i= 20 m/s. Final velocity should be 35.80 or 36 m/s when rounded to significant digits after using the correct initial velocity of 20 m/s.
Thank the lord!
Thank you for catching that. I was thinking he was using the 30^2 (Theta) as Vi and it was confusing me.
i was wondering why i got it wrong, glad im not the only 1 who was confused about the 30
sir, you could have solved the problem faster if you divided Vi into Vix and Viy. from Viy you could have solved for time(2Viy/g+kinematic equation for distance) and then plug in the time value to get Vfx (which is the same) and Vfy from one of the kinematic equations . Anyway, your videos are really great .
Wonderful lecturer that makes physics fun and understandable !!!
I wish have a teacher like you Sir
Sir please take a look: A projectile is thrown from ground with velocity 8 m/s. When it is moving with 6 m/s, it is at maximum separation from the point of projection corresponding to the speed 6 m/s. Then this maximum separation corresponding to speed 6 m/s is k meter. Find the value of k
There's something in the equation I don't get... Vfinal=sqrt(Vinitial^2+2gh) >> Vfinal=sqrt(30^2+(9.8)(45)). Why was Vinitial substituted by 30? Wasn't it supposed to be 20 m/s? Thanks for clarifying.
Justina,
Ah, excellent catch! Yes, there was a mistake at the 7:11 mark. Should have used 20 m/s for Vinitial. Well done.
Cheers,
Dr. A
Thank you for clarifying this. My students also noticed this. ❤️❤️❤️
His skill is mind blowing.
Great teacher
I'm still trying to rationalise this situation, is he behind the glass and if yes how is he able to write and draw with such pinpoint accuracy?🤐🇿🇦🙆🏽♂️
His skill is bind blowing.
Very very nice teaching thank you so math ❤
Im just thinking about it, its 8 years ago and I'm just watching it now
this makes so much sense
Excellent. Hopefully that continues.
Cheers,
Dr. A
Professor Anderson. Thank you for the wonderful lectures. I comprehend them completely but I couldn't completely understand a part of it i.e. why is Vyf the same as Vyi in the example that you gave us to understand the concept. I concur with you for Vxi=Vi=Vxf as there is no specific acceleration provided that we ignore the air resistance but in the y coordinate the object does undergo an acceleration due to gravitational force while moving downwards.
What time point in the video?
Cheers,
Dr. A
@@yoprofmatt 10:00 in the video why is the final velocity at the ground the same as the i itial velocity with which you throuw it against it
Where are you writing sir I am confused why you take 30 in place of 20 its wrong or not?
THANK YOU! i thought i was wrong lmao
Superb!
There is no influence made by an angle that is equal to 30 degrees to the V initial?
Correct. If the question is just about final speed, the initial launch angle is irrelevant.
However, if you asked a different question, such as how long is it in the air, then the initial launch angle does come into play.
Thanks for the question.
Cheers,
Dr. A
Matt Anderson thanks sir
so helpful thx a lot
Hello Dr, when do we ignore the negative sign of gravity when calculating? I noticed when you substituted the values while getting the square root of Vi^2+2gh that gravity is written as 9.8 and not -9.8. I get that it's so we don't get an error when calculating because it's a square root, but what's the concept behind this? I hope someone answers. TIA!
Also, does the formula Vf = sqrt(Vi^2+2gh) apply to all forms of projectiles? Would be really neat if it did.
hey that's because h is also negative due to the nature of displacement. it will turn out to be positive when multiplied with negative g. sorry i just realized i'm seven months late but i'll comment for the heck of reinforcing it in my head
We never ignore the sign. It's always negative 😉
How does Vi change from 20m/s to 30m/s??
Because I made a mistake, that's how. Great catch.
Cheers,
Dr. A
vf= 35.81 m/s
t=3.23 s
i hope im right cuz ive been studying for an exam soon..
Hello teacher. How can I find the shooting angle of a ball to hit a basketball hoop, if I have the speed, gravitational acceleration and vertical and horizontal distances?
I can't deduce an equation to find the angle when the target is above the launch point.
Excellent
Cheers,
Dr. A
We did this in 11th standard
the lesson was nicely enjoyed by kelvin kipngetich
KIPNGETICH KELVIN,
Thanks for the comment, and keep up with the physics!
You might also like my new website: www.universityphysics.education
Cheers,
Dr. A
very nice teaching
Thank you. I enjoy it.
Cheers,
Dr. A
i think under the square root the value of Viy should be Vi cos not 30 squared
Hi prof. Why did you choose the gravity -9.8 since the object rise then falls as it moves with direction of gravity then against it
How does the angle not matter? If I throw the ball down it will hit with a higher velocity then if I throw it up and let it fall down, right?
You can either "throw" a ball up OR "let" it fall down, but you can't do em together. I hope you understand the HUGE difference between the two. If you do, your doubt will get cleared, BTW your statement is wrong!
I calculated the time to be t=1.45 s but negative. Could you clarify how I may have accidentally obtained a negative? Thank you. I used the kinematic equation without acceleration: y=yinitial + 1/2(Vinitial + Vfinal)t
Rachel Barocio see if you have to divide time by something with negative
Try this video and see if it helps:
ruclips.net/video/ZPaRFr_3g2k/видео.html
Cheers,
Dr. A
Where he is writing
how can i contact you professor? i have a physics problem i'm studying for my final and it's really necessary 😢
What is that screen he is writing on? How can he writes backwards?
At 2:58 how did he take away the 2 that was next to the acceleration from the original kinematic equation
cuz acceleration is 0 in the x direction. so a = 0
i am kiran from pakistan.and sir is there any easy way to leran about projectile motion because its so difficult topic for me to understand ?
How to solve it without initial velocity?
is this formula also applicable in zero launch angle?
Yep.
Cheers,
Dr. A
wow am enjoying the lessons # EJ
I guess we could also use energy to solve this questoon (mgh and KE)
Absolutely. You're looking ahead.
Cheers,
Dr. A
wait how are you writing backwards what the heck
how can we get the angle of vf?
The vector drawing at 5:38 should tell you how to calculate the final angle for vf.
Cheers,
Dr. A
When Vf=√Vi²+2gh why Vi²=30
Because gives angle is 30 tell me Proffesior
No it's wrong because sin30= 1/2 so
Vi2= (20×1/2)2 = 100
Благодарю
initial velocity was 20 not 30
Yep. Thanks for paying attention.
Cheers,
Dr. A
There is the biggest mistake that the professor made which Vi is equal 20 and it is not 30
Sir can you plz explain v-t,a-t,s-t,a-s
V-s graphs
Here you go: ruclips.net/video/senmYqnOYz8/видео.html
Cheers,
Dr. A
i got vf =35.68 m/s and t= 4.2s
I saw complete video just to know how you write in reverse direction
sagar kadam,
Not writing backwards (I'm not that talented). The board is called Learning Glass. You can check it out at www.learning.glass
Cheers,
Dr. A
I am gonna marry that girl who answered -9.81.
Better master your physics then!
Cheers,
Dr. A
please tell me what your software sir ....
tell me
www.learning.glass
would this still work with h=0?
Adrian Chaix,
Yes of course.
Thanks for the comment, and keep up with the physics!
You might also like my new website: www.universityphysics.education
Cheers,
Dr. A
Oh god the squeak on that board is irritating.
Imagine standing right next to it. Awful.
Cheers,
Dr. A
I don' understand anything
🌹
saved my life #considerthisvidliked
i dont get ittt
What don't you get? Perhaps I can help.
Cheers,
Dr. A
I finished my PHY exam.. Thanks anyway ... + I LOVE YOUR VOICE
Shut that damn bird up!!!
سبوره شفافه والا شنو 😂
I don't think Google translate worked properly for this comment, but thanks anyway.
Cheers,
Dr. A
اخيرا مصري
man, you are so handsome
2:52 sir a planet with a name earth has acceleration due to gravity 9.8m/s^2
Nitin Nitin Dude, The acceleration in X-axis is zero on earth
The gravity is pull us back only in y-axis
It would be crazy if it's pull us forward hahaha
Don'tTellDon'tSeeOfficial 😅
Don'tTellDon'tSeeOfficial thanks
But Physics is so hard for me anyway 😂
Did you ever do a how far it hit the ground?
glorymanheretosleep,
Not sure if I did. Seems like I must have done that somewhere.
Thanks for the comment, and keep up with the physics!
You might also like my new website: www.universityphysics.education
Cheers,
Dr. A