My teacher apparently estimates each week's assignments to be 1.5-2 hours a week. They literally take 3-5 if you actually try hard enough. Actually even more
I noticed a lot of people asking where the -16 comes from. This particular variation of the quadratic is a _physics_ formula, h(t) = -1/2 * g * t^2 + v0 * t + h0, where h(t) is height as a function of time, g is the acceleration due to gravity on Earth (9.8 m/s^2 or 32 ft/s^2), v0 (pronounced "vee naught") is the initial upward velocity in feet per second, and h0 (pronounced "aych naught") is the initial height of the projectile above the ground. 32 * (-1/2) yields -16, which becomes the coefficient for the t^2 term. And yes, if you're on Earth (and using English units instead of metric), -16 will _always_ be the coefficient of that first term. I hope this helps for future viewers.
isn't it faster to use the d= r.t formula? (distance = range(speed).time) We are given distance 50 and speed 20 ft/s, so it's 50=20t, now we just flip it to 50/20 = t and simplifying it its 5/2
You didn't have to use the quadratic formula, as -5 and 5 multiply into 25 and 4 and 2 multiply into 8 and the sum of their product gives you -10, so you might as well write 0= (4x-5)(2x+5) and solve for the x values by setting them to 0 individually.
I have a problem solving this word problem: A square lawn is surrounded by a concrete walkway that is 2.0 m wide. If the area of the walkway equals the area of the lawn, what are the dimensions of the lawn? express the dimensions to the nearest tenth of a meter. I have tried many times modelling the problem but always get stuck, can u please help. Thanks
The equation is easy to follow, However - It would be nice to know where the -16t squared comes from. -16xsquared must be a standard but this problem doesn't explain where one can find such a (seemingly) constant value to plug into the equation. Is there a list or table somewhere with such information?
To simplify the equation, doing that would make it easier to solve. If you don't simplify you'll get the same answer but it would just be harder. He did -2 because they're divisible by that number.
the answer has to be neg, you could already tell by the beginning of the prob, "A ball is shot into the air" by that the ball already the ball has some sort of the velocity when it reaches the edge of the building. now keep on mind they want to know how long it takes to hit the ground. well thats where the neg answer comes from bc it already trav at a x speed. to find a pos answer we first have to know at force/speed it was thrown up in the air. now the force its tricky bc depending on the force the ball could of travel upwards reaching x altitude, picked up x speed downward, and this is not taking in consideration the weight of the ball and so on blah blah.
it said, it initial velocity is 20ft per sec, this is the velocity when it met at the edge of the building. the problem should of had started like, a ball is drop from the edge of the building....
I have a test tomorrow I still don't get any of this
We're on the same page
Sophia S bruh same
why don't you get this
don't feel bumb out
Same, but I hope you still did good on the test.
Me in quarantine: laughs in Photomath
ROZELLE photomath works for this?
@@tylersakul2633 if you take a picture of the formula then yeah...
Casuals
Lmao yes
HAHAHAHAAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHHAHAHAHAHHAHAHHAHAHAHHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHHAHAHAHAHHAHAHAHAHAHAHAHAHHAHHAHAHAHHAHAHAHHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAH
When are you ever going to use this in real life ? Unless it's for your job.
Baseball
David Chillton frr
Business applications it's the same concept from same formula.
i kinda believe we should focus more on this than others because like its basic physics but this isn't explained as well and as much
Shut up and learn
My teacher apparently estimates each week's assignments to be 1.5-2 hours a week. They literally take 3-5 if you actually try hard enough. Actually even more
That sounds frustrating
I noticed a lot of people asking where the -16 comes from. This particular variation of the quadratic is a _physics_ formula, h(t) = -1/2 * g * t^2 + v0 * t + h0, where h(t) is height as a function of time, g is the acceleration due to gravity on Earth (9.8 m/s^2 or 32 ft/s^2), v0 (pronounced "vee naught") is the initial upward velocity in feet per second, and h0 (pronounced "aych naught") is the initial height of the projectile above the ground. 32 * (-1/2) yields -16, which becomes the coefficient for the t^2 term. And yes, if you're on Earth (and using English units instead of metric), -16 will _always_ be the coefficient of that first term. I hope this helps for future viewers.
can you make more application word problems? using that formula?
Thanks SOO much!! This was SO helpful for studying!
khan academy pulling through rn 🙏
What if you get positive answers for both x-intercepts? Then which one do I have to choose as an answer?
Then both answers are correct.
Why is positive 4 it should be negative right if you multiply -8 times -25 the product is 200 times negative 4
The quadratic b2-4(a)(c)
isn't it faster to use the d= r.t formula? (distance = range(speed).time) We are given distance 50 and speed 20 ft/s, so it's 50=20t, now we just flip it to 50/20 = t and simplifying it its 5/2
You saved ma life
Kahn Academy. You have caused me so much pain and suffering in the math department. 😭
How would this work if solving for an percentage and a specific year equation?
It really is very easy when one knows the system
Really useful ,more example like this would be great
I had to finish a take home assessment and this helped a lot man, thanks. I fucking hate algebra
and for all y'all who saying "slow down" it's called pause the video and work your problem slowly, genius
Simply "I hate algebra" would have worked better.
stop reading comments and study
lmao
Where did the 16t² come from?
It was in the equation given in the problem
Me rn;
How you like that?
Guys! Can you teach me how to solve this lesson? Huhu
Khan academy i love you
im confused on how to this when your discriminant is negative though -____-
the square root of -1 is i
I am wondering of the first term's origin, where does -16t^2 comes from?
Same
Thts the stretch factor
is the way that you did it longer?
because i automatically just applied the quadratic formula and still got the correct answer but quicker
is he writing on the computer or on a pen to computer image software?
You didn't have to use the quadratic formula, as -5 and 5 multiply into 25 and 4 and 2 multiply into 8 and the sum of their product gives you -10, so you might as well write 0= (4x-5)(2x+5) and solve for the x values by setting them to 0 individually.
Can u please explain me why did he divide the equation by 2 at first?
3 years late but he did that just to simplify the function! It's not necessary, but it makes your values easier to work with
@@haani4745
SLOW DOWN
I have one question, Where did you get 16t?
Gravity is 32ft per sec ² and the equation you originate the formula from is -1/2 of that so -16x²
Does that apply to all equations?
thanks for the help
Where does the -16 come from?
I have a problem solving this word problem: A square lawn is surrounded by a concrete walkway that is 2.0 m wide. If the area of the walkway equals the area of the lawn, what are the dimensions of the lawn? express the dimensions to the nearest tenth of a meter.
I have tried many times modelling the problem but always get stuck, can u please help. Thanks
u still need help
Zdark X 😂😂
The equation is easy to follow, However - It would be nice to know where the -16t squared comes from. -16xsquared must be a standard but this problem doesn't explain where one can find such a (seemingly) constant value to plug into the equation. Is there a list or table somewhere with such information?
this is helpful
Where did you get the 16t2?
ProGone DO YOU KNOW?? I NEED HELP
It’s from the equation that they gave you
but ; maths does not give waste answer...; then what does that (-5/4) mean???
means the ball started has dark matter, neg velocity
then; kinematics must be apply!
It means you can't simplify any more
Why would it had to divide them by negative 2? Why??
Why divided by -2? 1:30
To simplify the equation, doing that would make it easier to solve. If you don't simplify you'll get the same answer but it would just be harder. He did -2 because they're divisible by that number.
@@moodafan123 but why negative 2 ? neither positive 2?
Why didn’t you use the simplified equation when confirming that h is zero at the end? Is it not allowed or something?
b^(2) - 4ac = 900
Hmmm...I'm in AP Physics C, this is a kinematics problem.
Ok it's all good until you changed the equation by multiplying 2. I don't get it.
Yeah even I don't get that
He factored the equation
Bruhhhhhh your amazing
Whawha....?
This didn't have me cause ya writing on a black board and I can't see it good
the answer has to be neg, you could already tell by the beginning of the prob, "A ball is shot into the air" by that the ball already the ball has some sort of the velocity when it reaches the edge of the building. now keep on mind they want to know how long it takes to hit the ground. well thats where the neg answer comes from bc it already trav at a x speed.
to find a pos answer we first have to know at force/speed it was thrown up in the air. now the force its tricky bc depending on the force the ball could of travel upwards reaching x altitude, picked up x speed downward, and this is not taking in consideration the weight of the ball and so on blah blah.
it said, it initial velocity is 20ft per sec, this is the velocity when it met at the edge of the building. the problem should of had started like, a ball is drop from the edge of the building....
Let me know when you can go back in time, and then ill believe you.
this one dude with that huuuge explanation
why would someone want to calculate something like this? why are these problems always like you are solving for the heck of it. how boring.
What about solving for height
C.W R.W height becomes the h in y=a(x-h)+k which is also called the vertex form
The maximum height rather
where did the negative 16 come from
i love you
Can you solve this without simplifying? I got 60/-32 which = -1.875
San nyu po nakuha ang 16?
He's never claimed to be Muslim. Just because his name looks Bengali doesn't mean he's Muslim.
im failing bruh
SAME IDK WHAT TO DO UGHHH
Wi juytre loke truhb
I got test tommow, but I don't get it.
Where he get -16 from
Why u use the square root
Sir, can I use the bathroom?
wait, i don't get why you divided it all by two?
You can just factor out a -1 to make it positive he did the most
Can someone tell me where -16 came from? :
given
-16 t kha sy a gya smJ nhi aya😮
FUCK YEA!!
FIRST COMMENT!!!
congrats
*coughs* the heck
Bruh you don’t have to simplify
Bhai ye banda dusro ka vedio copy paste karta hai
Who is here 2024 😂
Someone help me...the question I'm trying to answer just give me the equation and no other.Any Idea?
Good job my Muslim brother!
You should do some Islamic lessons and people will actually listen to you because of your wide knowledge!
You can just divide 50 by 20. Duh.