Treating systems (the hard way) | Forces and Newton's laws of motion | Physics | Khan Academy
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- Опубликовано: 5 сен 2024
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Physics on Khan Academy: Physics is the study of the basic principles that govern the physical world around us. We'll start by looking at motion itself. Then, we'll learn about forces, momentum, energy, and other concepts in lots of different physical situations. To get the most out of physics, you'll need a solid understanding of algebra and a basic understanding of trigonometry.
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Thank you! The "hard way" is actually very necessary to learn. Now I understand why the magnitude of the acceleration is the same for objects in a system
Very helpful! Your way of teaching is almost as good as Sal.
Thanks for this, really good explanation.
This one looks like an easy way.
Thanks, David.
Anyone else have to re-watch that video a few times? At first I was on-board, but by the end I was so focused on writing it down that I got confused a little. Once I wrote it down, I re-watched it to fully understand what to do. Trying to teach myself some basic physics.....so far so good. Love the videos by the way, keep up the good work!
Allison Douglass no.....no one else was like u
Amazing technique, so much simpler than what my teacher taught us. Thanks as always.
Thankyou for this video! It's not that hard to understand at all :)
Thank you for your videoQuestion: If you are going to say acceleration in the y direction is the negative of the acceleration in the x direction, then why do we not compute the tension force in the same way?
if u mean to say that why the tension isnt negative for the 3 kg it doesnt rlly matter. What matters is the magnitude
I don't understand, if the 3kg mass is accelerating downwards, wouldn't it be positive acceleration as well? I thought negative acceleration would be deceleration, similar to how when we sub values into our SUVAT equations we put in -9.81ms^-2 when the particle flies upwards before it comes to a halt (v=0) at maximum height. Please can you explain? Thank you very much!
Just understand and use Cartesian sign convention. Then you will understand why.
Can we measure the distance from the block to the end of the table, find the time it uses to cross that to find the velocity and then find the acceleration?
No
You could, but when the problem doesn't have that information, then you'll have a slight problem. (pun intended)
But isn't it easier to treat positive direction as forward and then downward?
How can horizontal and vertical tension be equal
If you pull two ends of a rope, both ends will have equal force acting upon them
thanks
Thanks!!! This was great!
Excellent explanation! Thank you so much
i think the confusing part is the (-) sign. don't take it in the mathematical sense but simply see it in terms of direction (+ means right or up, - means left or down) cuz' if u think about it, how can a (-) number ever equal to (+) number?
How did u turn it from a=T/5 to T=5×a at 6:37?
better way-> 3g-0=8a
a=3/8g
Isn't the negative sign used just for deceleration?
it is now meant for the direction to avoid confusions
The negative sign shows direction. Think about this. If you choose rightward as positive and leftward as negative, and the object is moving to the left and accelerating, it will be going faster and faster in the negative direction. It is thus not decelerating, but accelerating, yet the acceleration is negative (since it is accelerating to the left).
@@pierreretief I know it's already several months late but I'm still confused as hell. So how should we supposed to write deceleration then if negative and positive sign is used for direction?
thank you so much i finally get it
Woah, this is extremely easy.
Thanx. 👌👌
wow it gave me a lot of advantage to be honest
I don't get why the acceleration of the 3 kg mass must be negative. Does that mean that if the 3 kg mass and pulley were on the left, the acceleration would somehow be different?
On an xy graph, down and to the left are negative. up and to the right are positive.
Why is the tension of the string on top of the 3kgmass not equal to the force exerted by the product of its mass and acceleration? In other words why is the tension smaller than 29.4 Newtons?
If the normal force on the 5kg mass is equal to the product of its mass and acceleration, why can't we assume the same situation on the 3kg mass?
because it is accelerating in the same direction as Fg
if it was straight line motion in 1d then u could take something as the negative of other but this is I direction and j direction so how can u just take then as equal? they r not the same as direction is different and u can't say a along X axis = a' along -y axis. it makes no sense as they r different axes
For me it made sense at least.... but dont listen to me I read book trilogies always starting from the second book.
Thank you so much. My professor is just awful at explaining things.
Is there anybody here to know what application does this dud work with?
This isn't Sal
I keep hearing 3 &5 kilogram 'ass'
Wonder how much that guy gets paid.