Treating systems (the hard way) | Forces and Newton's laws of motion | Physics

Treating systems (the hard way) | Forces and Newton's laws of motion | Physics | Khan Academy

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8 жыл бұрын

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Пікірлер: 43

@aldreivohnaquino3100 3 жыл бұрын

Very helpful! Your way of teaching is almost as good as Sal.

@uchihamadara6024 7 жыл бұрын

Thanks for this, really good explanation.

@dilshodbekramazonov3804 Жыл бұрын

This one looks like an easy way. Thanks, David.

@antaresrepublic 3 жыл бұрын

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

@tanishshah8514 6 жыл бұрын

Amazing technique, so much simpler than what my teacher taught us. Thanks as always.

@ricaramirez5411 7 жыл бұрын

Thankyou for this video! It's not that hard to understand at all :)

@allisondouglass5549 7 жыл бұрын

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!

@nirmitbatavia8192 6 жыл бұрын

Allison Douglass no.....no one else was like u

@horsexaba8560 5 жыл бұрын

Excellent explanation! Thank you so much

@herrschultz7413 7 жыл бұрын

Thanks!!! This was great!

@chithrakumarasamy7528 7 жыл бұрын

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?

@zouraizkhan2467 4 жыл бұрын

if u mean to say that why the tension isnt negative for the 3 kg it doesnt rlly matter. What matters is the magnitude

@hugeturnip3520 4 жыл бұрын

thank you so much i finally get it

@PDog69 6 жыл бұрын

thanks

@erickjoshuanebreja6154 5 жыл бұрын

wow it gave me a lot of advantage to be honest

@ishankatoch7245 7 жыл бұрын

Thanx. 👌👌

@johnfei434 5 жыл бұрын

But isn't it easier to treat positive direction as forward and then downward?

@aidenwinter1117 6 жыл бұрын

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!

@whoreslayer Жыл бұрын

Just understand and use Cartesian sign convention. Then you will understand why.

@amarachiaguwa1781 5 жыл бұрын

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?

@dhruvmk3055 4 жыл бұрын

@himanshujangid9493 Жыл бұрын

You could, but when the problem doesn't have that information, then you'll have a slight problem. (pun intended)

@jacob-jm2xp 3 жыл бұрын

Woah, this is extremely easy.

@Melody429IU 4 жыл бұрын

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?

@howtoeataham 4 жыл бұрын

Thank you so much. My professor is just awful at explaining things.

@bansuripranayama 4 жыл бұрын

How can horizontal and vertical tension be equal

@fmpairsoft9039 3 жыл бұрын

If you pull two ends of a rope, both ends will have equal force acting upon them

@gonzalomeadearanda5751 6 жыл бұрын

For me it made sense at least.... but dont listen to me I read book trilogies always starting from the second book.

@1Manhunt7 2 жыл бұрын

How did u turn it from a=T/5 to T=5×a at 6:37?

@administracaounib5222 6 жыл бұрын

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?

@chiman3778 6 жыл бұрын

On an xy graph, down and to the left are negative. up and to the right are positive.

@groovyfx6326 6 жыл бұрын

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

@princessdoza1060 7 жыл бұрын

Isn't the negative sign used just for deceleration?

@erickjoshuanebreja6154 5 жыл бұрын

it is now meant for the direction to avoid confusions

@pierreretief 5 жыл бұрын

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).

@yiumyoumsan6997 4 жыл бұрын

@@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?

@ambience.007 Жыл бұрын

better way-> 3g-0=8a a=3/8g

@farbodgilandoust6674 Жыл бұрын

Is there anybody here to know what application does this dud work with?

@Kaizer-pt5vk 7 жыл бұрын

I keep hearing 3 &5 kilogram 'ass'

@AM-rf3zn 7 жыл бұрын

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?

@kingplunger6033 4 жыл бұрын

because it is accelerating in the same direction as Fg