My Physics teacher just assigns us Khan assignments and Edpuzzles, and poorly teaches the lessons. He’s a nice teacher, though, just not very good at his job.
in minute 3.06 you mention that velocity is directly proportional to the radius. When we talk about angular momentum and there is absence of torque, angular velocity is inversely proportional to the radius. Why is it?
If an object isn't anchored at a point i.e it's rotating freely without any pivot, will it always rotate about it's center of mass, no matter if it's an irregular shape?
There is no kinetic energy in a moving mass there is force Mv squared kinetic energy is the energy of consistent work from a consistent force regards Graham Flowers
It's quite hard to believe that, say the baseball flying has a kinetic energy of about 116J, and all these energy came from the one hurl that the sportsman threw (likely within 1s and within 1m of arm movement)? This kinda infers that the sportsman used (more than) 116J in that short period of time!!! According to my treadmill, it would take about 10min to run at a speed of 8.5 km/h to use that much energy. Can a baseball go as fast as 40m/s?! I know that badminton can go really fast but they are much lighter. ------ Update: I made a mistake in units. Running on a treadmill at 8.5km/h for 10min would spend about 100 kCal, not J.
You won’t find a baseball with a diameter of 14cm (nearly half a measuring rule) 😂 Otherwise, good video mate Edit: after a quick google search, I think you accidentally took the diameter of a MLB baseball and used it as the radius. I only checked because the numbers sounded funny to me. Best wishes mate!
It was a simplifying assumption, otherwise the density is not the same throughout the ball and we can't treat it as a constant and pull it out of the integral and need to account for it while integrating. Also if we don't know how density changes (with what function) we can't integrate it at all.
That way you can pull your arm back faster, it also increases the likeliness of a punch causing, or aggravating a cut, and causes your shoulder and deltoid to twist up and cover your jaw. That plus the fact that a punch should be delivered with the palm facing down (less likely to damage your wrist like that), and you don't usually hit from a palm facing down position, so you should be twisting your arm anyway. Don't trash talk people and what they're doing if you don't know anything about it. Sorry for my bad english.
You might be the greatest Physics teacher ever.
You just might
No cap
Shut up! Tusk act 4 rotate his balls!
I love that this guy can teach us for free, and still a much better job than my mechanical engineering lecturers that are being paid 90quid per hour
My Physics teacher just assigns us Khan assignments and Edpuzzles, and poorly teaches the lessons. He’s a nice teacher, though, just not very good at his job.
Khan Academy really does in fact teach me that I can learn anything! Thank you :)
Thank you for doing physics lecture. Please keep doing more lectures.
thanks... these lectures really help me in flourishing my concepts about physics terms
So so so so clear! Thank you
So helpful, many thanks!!
I love this guy's lectures. The other guy with that surfer-dude voice always beats around the bush too much.
I think you are the next Einstein and a good teacher too😁😁😁😁 THANK YOU
I went from making D's to A's in my physics class because of your physics videos, thank you so much!
Thank you my brother. Long live the king!
Top notch explanation
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Thank you 😊😘
Could you integrate angular momentum to get angular kinetic energy?
nope, L =MVRSin(theta) and kinetic energy of a rotating body is 1/2 Iw^2
but the relation between gular momentum and kinetic energy is
L^2= 2I/K.E
Beautiful ❤️
Thank you
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great video! thanks Khan!
Beautiful
11:34 where can i see the derivation?
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tnx :))))) it helped
I love you bro !!!
in minute 3.06 you mention that velocity is directly proportional to the radius. When we talk about angular momentum and there is absence of torque, angular velocity is inversely proportional to the radius. Why is it?
excellent. thanks.
Can anyone explain why omega is same for Every particle?
🤔🤔
awesome but not availiable on official site of khan acADEMY
Great explanation. Thank you!
Why is here Angular speed constant every where? In the previous lesson you said radius and Angular speed are inversily proportional (e.g skating
Thank you!
If an object isn't anchored at a point i.e it's rotating freely without any pivot, will it always rotate about it's center of mass, no matter if it's an irregular shape?
What is the difference between this and the Magnus effect/force?
Can u explain why the surface integral of a sphere is in terms of the eccentricity rather than the radius ?
Why does the same momentum give extra energy in the form of rotation?
maja aagya sir
There is no kinetic energy in a moving mass there is force Mv squared kinetic energy is the energy of consistent work from a consistent force regards Graham Flowers
Nice
in MLS they play with there foot not hand. And they don't throw they shoot
So why do moons/stars spin backwards creating an angular problem?
What if I told you, I'm making a java program and I am now FORCED to learn about kinetic energy for it! WHY?!
"I'm making a java program" rip
FYI--You said the diameter was 7cm but you used 7cm as your radius.
It's quite hard to believe that, say the baseball flying has a kinetic energy of about 116J, and all these energy came from the one hurl that the sportsman threw (likely within 1s and within 1m of arm movement)? This kinda infers that the sportsman used (more than) 116J in that short period of time!!! According to my treadmill, it would take about 10min to run at a speed of 8.5 km/h to use that much energy.
Can a baseball go as fast as 40m/s?! I know that badminton can go really fast but they are much lighter.
------
Update: I made a mistake in units. Running on a treadmill at 8.5km/h for 10min would spend about 100 kCal, not J.
They can travel at 40m/s... while rotating. So, it basically has the speed of 40m/s, but its velocity is not that big.
You won’t find a baseball with a diameter of 14cm (nearly half a measuring rule) 😂
Otherwise, good video mate
Edit: after a quick google search, I think you accidentally took the diameter of a MLB baseball and used it as the radius. I only checked because the numbers sounded funny to me. Best wishes mate!
Baseball is a solid ball?
It was a simplifying assumption, otherwise the density is not the same throughout the ball and we can't treat it as a constant and pull it out of the integral and need to account for it while integrating. Also if we don't know how density changes (with what function) we can't integrate it at all.
Arigato, Gyro
🙏🙏🙏🙏🙏
All the martial artists who claim that rotating and screwing the fist will add damage to a punch can shut up now.
That way you can pull your arm back faster, it also increases the likeliness of a punch causing, or aggravating a cut, and causes your shoulder and deltoid to twist up and cover your jaw. That plus the fact that a punch should be delivered with the palm facing down (less likely to damage your wrist like that), and you don't usually hit from a palm facing down position, so you should be twisting your arm anyway. Don't trash talk people and what they're doing if you don't know anything about it. Sorry for my bad english.