Force of friction keeping velocity constant | Physics

Force of friction keeping velocity constant | Physics | Khan Academy

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13 жыл бұрын

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Calculating the coefficient of kinetic friction (correction made in next video). Created by Sal Khan.
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Пікірлер: 38

@fleshcookie 11 жыл бұрын

" Lets think about what friction is up to " Sal cracks me up. You can tell this is total childs play to him

@gabby3220 5 жыл бұрын

My physics teacher just tells us what each force is, like what direction it is, and expects us to know how to solve his problems. Thank you for this you are a life saver.

@birendramanjhi3160 2 жыл бұрын

pppp

@petmakahan7799 6 жыл бұрын

Would it be possible to put these videos into lists where the sequence from one to another is clear? The videos I watch sometimes lead onto another one, as promised; however, there are also occasions where a future video is referred to, but nothing shows up on the sidebar (and one doesn't know the title of the next video, and can't look it up).

@justrandomthings709 3 жыл бұрын

Do you have any examples on horizontal surfaces?

@UltimateSAB 13 жыл бұрын

You are the best!! This is helping me for my exam in two days!

@ericmigueldelfuerte1151 10 жыл бұрын

someone pls link the full video of the first problem in this video. thank you :)

@piratemorocco 12 жыл бұрын

@SirCattlemenJoeseph It is 98*(√3/2) which is 49*√3 [(98/2) = 49]

@glendasworld4125 7 жыл бұрын

The force of friction and the force perpendicular to the left of the box are the same as in the last video. In the last video, the box is stationary. But in this one, it is moving. How's that? In the first video it made sense because the forces cancel each other out leaving no movement. But in this one it doesn't make any at all.

@faterosario7872 6 жыл бұрын

have question: Consider a weird place where the force of friction acts in the same direction as objects move. If an object were given a small push to start it moving and then observed as it moved with only the force of friction on it.......?

@anoobgamerNG 6 жыл бұрын

Hey sal thnx for amazing videos... Hey why dont you add animation and vfx subjects?? Here in india ppl so unaware nd thinks its childish

@LISA.WANG. 4 жыл бұрын

Does the velocity matter since the acceleration is zero? Also what if that block were being pulled _up_ the ramp at a constant velocity, would the required force change if it was being pulled at 5 m/s compared to 100 m/s? And if it were being pulled upwards, would it have to overcome both friction and the parallel gravitational force together?

@troylewis6265 10 жыл бұрын

Wait where did the velocity come into play? If it was moving at 100 mph would the coefficient of kinetic friction be the same?

@sherifzineldine4207 4 жыл бұрын

This comment is six years old but I'll answer it for others inquiring. I believe that was just an example the velocity would depend on how much it accelerated which would depend on the force applied beyond kinetic friction and how much time passed.

@sunnythind8574 3 жыл бұрын

@@sherifzineldine4207 appreciate you answering it because I had the same question

@mamatheshkumar5711 2 жыл бұрын

kinetic friction may have velocity speed acceleration deceleration uniform arbitrary.

@sajjankrpichalangia8130 3 жыл бұрын

Dank rishu

@gabrielsanchez8501 9 жыл бұрын

Just a little confused here. When the object is stationary (previous video): Force going parallel to surface and downwards was 49N and Force of friction was also 49N (this makes sense to me because the forces on either side are in balance, thus nil movement) When the object is moving down the slope (this video): Forces are the same as the stationary situation (i.e. 49N and 49N). Wouldn't the force that is parallel to surface and moving downwards be HIGHER than Force of friction, since it's moving down a slope?? Scratching my head and I know the answer should be simple

@gabrielsanchez8501 9 жыл бұрын

Okay, so I've looked at this video again and realised that: An object at constant velocity will have the same forces acting upon it as the same object when stationary (Newton's 1st law). Quite difficult to fully understand this concept so that it makes logical sense to me. In my mind, it would seem that an object that is stationary and one that is at a constant velocity would have completely different forces acting on it, however I know that is not the case

@shenmaluren 9 жыл бұрын

Gabriel Sanchez same thing happens to me

@glendasworld4125 7 жыл бұрын

Rigo This helped a lot. Thank you. I was having trouble understanding this too.

@luongmaihunggia 6 жыл бұрын

Do you even know about Newton's first law? Did you even watch his earlier video?

@a4q2020 2 жыл бұрын

We could see how much effort you put into creating a video. Super.👍 We A4Q team with your growth. Full support 💪

@rubinaakther5665 3 жыл бұрын

Where are you now

@shubhamjoshi3861 2 жыл бұрын

Ohh hello

@beacr5880 11 жыл бұрын

don't say that, like ours are any better than yours

@youtubeessentials2996 2 жыл бұрын

Both videos are wrongly answered

@beautygamer606 9 жыл бұрын

WHEN IS GRAVITY PERPENDICULAR TO THE PLANE?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?!?! IT IS ALWAYS PERPENDICULAR TO THE GROUND!!!!!!!!!!!!!!!!!!!!!!!!!!

@GaneshKumarIIT 9 жыл бұрын

Gravity is not perpendicular to the Plane. When you decompose or resolve force of gravity ( = mg ) in two directions , one along the plane and another perpendicular to the plane , you get a component of gravity that is perpendicular to the plane.

@VibhaMasti 8 жыл бұрын

The force of gravity (98N) was broken down into its horzontal and vertical components with respect to the surface of the slope (98 sin 30 and 98 cos 30).

@rafiatbm7867 6 жыл бұрын

exactly