Physics 10 Momentum and Impulse (11 of 30) Ball Hitting Wall: Ex. 1

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10 жыл бұрын

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In this video I will find F=? when a ball strikes a wall, example 1.

Пікірлер: 110

@winenoob 7 жыл бұрын

Thank you for all your videos! I would not survive Physics without you

@tuna34joseph 6 жыл бұрын

excatly

@ste5402 6 жыл бұрын

Loved this lesson!

@ironuranium3927 5 жыл бұрын

if we find arctan(5000/10000) have any meaning of this angle?

@LuizaCarvalheira 5 жыл бұрын

you are an AMAZING teacher

@celestialxitshembiso3696 Жыл бұрын

Really helpful ....going to write my engineering science tomorrow with confidence 🙏😊😊

@GEEONTHEBEAT 5 жыл бұрын

TYSM Proffesor!!! Cool bow tie too :3

@kaabsabah85 4 жыл бұрын

many thanks for effective and methodical teaching

@paulostipanov7682 5 жыл бұрын

What about the final force F? You've calculated only the force in x and y direction.

@alexicazee 6 жыл бұрын

My final is in an hour and this literally saved my life lol

@wrestlewithmagic123 5 жыл бұрын

Sir you are a lot helpful for students

@Vendal 5 жыл бұрын

Sir i have a question, does the force in the Y direction include the weight of the body, so if we want to calculate the force done by the wall to the body in Y direction would it be 5000-5x10=4950 N ?

@MichelvanBiezen 5 жыл бұрын

No, the force of the wall on the body is only the friction force. But the total force on the body is the friction force (up) - weight (down)

@borahtrinayan3 6 жыл бұрын

Fabulous video sir

@richperez5556 8 жыл бұрын

How does one do cos(36.9 degrees), in one's head? Great video.

@adityasaxena8212 2 жыл бұрын

you cant

@josephshaff5194 4 ай бұрын

Thank god! After watching I think I calc'd the Baltimore Bridge problem right roughly as a rough est.. It's been a yr or so since College Physics. Unfortunately, I destroyed my precooked crab dinner by boiling it. Gotta work on that. But I got the Physics right.

@MichelvanBiezen 4 ай бұрын

Sorry, no cookig classes on this channel. 🙂

@mariad1193 4 жыл бұрын

Hello Michel: Is the force exerted by the wall in the x-direction related to the normal force (reactionary force) pushing back at impact and the force in the y-direction (parallel to the wall) the frictional force? How do these forces affect the ball upon impact? Moreover, if we assume there is no friction when the ball hits the wall, how would I find the average force that is on the ball from the wall? Many thanks!

@bhawnaklair3681 3 жыл бұрын

Hi maria! I was really hopping someone got you an answer, because right now I'm having the same questions

@AlenRukavina 6 жыл бұрын

Is it possible to calculate the impact force in real life if we dont know the 'time in contact' value. For example to compare two forces, one of static brick on some surface as F=mg and a brick free falling from some distance. We know that the impact force has to be higher then the static force for the bricks with the same mass but how to compare it or calculate it? Thanks for your answer!

@MichelvanBiezen 6 жыл бұрын

If you don't know the time duration of the impact you will not be able to determine the magnitude of the force.

@bboymj3628 5 жыл бұрын

mean the quadrant

@anilkumarsharma8901 3 жыл бұрын

How much time⌚ ⚽⚽🏈🏀 balls swing before it's going to loose it's energy Completely?????

@Rohitkumar-yo8js 7 жыл бұрын

sir,can we apply the impulse formula if two object of mass m and 2m are stricking,for finding the force with which they strike??

@MichelvanBiezen 7 жыл бұрын

Only if you know 1) the time of contact, and 2) the force as a function of time. The other method would be to use: impulse = change in momentum

@estefaniac7324 Жыл бұрын

Thank you so much for all the examples regarding this topic! I'm working hard on understanding all the situations but I'm a bit confused about when the conservation of momentum is applicable or not. In this case, in which friction is involved, we can't use momentum conservation for reasons of simplicity in calculations, but the momentum is in fact conserved? Also, I understood that momentum conservation is applicable even for objects in free fall, is that right? Than you very much again for all your great work and invaluable help!

@MichelvanBiezen Жыл бұрын

Momentum is ALWAYS conserved, regardless of the situation. WIth friction, without friction, etc. Whenever there is a collision of any kind, we can be guaranteed that momentum is conserved.

@estefaniac7324 Жыл бұрын

@@MichelvanBiezen perfect!!! thank you very much!!

@anilkumarsharma8901 3 жыл бұрын

Impulse and movementum in terms of energy???

@HowTo5min-co3ni 4 жыл бұрын

Helpful!👊

@tankieag1117 Жыл бұрын

Should the two angles created by the horizontal line be equal to each other? Just like in the way of light reflection angle.

@MichelvanBiezen Жыл бұрын

That depends. If there is no friction between the ball and the wall, then yes. But if there is friction, then no.

@ajayreddy1761 5 жыл бұрын

what would happen if you did not have the mass of the ball and it was a linear collision no angles how would one find out the mass? I need the find the F and all i have is the velocity. Please help if you can thanks

@MichelvanBiezen 5 жыл бұрын

Start with the conservation of momentum equation and determine what the unknowns in the equation are.

@akilakavisinghe7189 6 жыл бұрын

What is the trick you are using when you are finding the sin and cos of those angles in your head?

@MichelvanBiezen 6 жыл бұрын

No trick. I just memorize a few of the angles.

@eneapane5831 6 жыл бұрын

Think about the unit square in the x and y coordinate plan. The x axis represents the cosine of an angle and the y axis represents the sine of an angle(relative to the x axis). Then you draw the radius of the circle which has an angle to the x axis of approximately 36.9 degrees. Now you can divide the radius into its components. You will see that the horizontal component is larger, which means that the cosine of the angle is the larger value( in this case between 0.6 and 0.8, the greater is 0.8)

@eneapane5831 6 жыл бұрын

Can't you use the pythagorean triple to come up with the module of the total force exerted on the ball?

@MichelvanBiezen 6 жыл бұрын

The best way to find out is to try it and see if you get the same answer.

@ironuranium3927 5 жыл бұрын

initial momentum in the x-direction is not equal to the final momentum in the x-direction 5*20*cos(53.1), not equal 5*10*cos(36.9) how this possible if momentum is ALWAYS conserved??

@MichelvanBiezen 5 жыл бұрын

Yes, this is something that often confuses students. Note that the wall is connected to the Earth and thus the remainder of the momentum is absorbed by the Earth.

@jenniekim2501 5 жыл бұрын

But sir, if we have to find the impulse how will be doing it with the forces that we obtained ?

@MichelvanBiezen 5 жыл бұрын

Impulse is defined in two ways: 1) I = F (delta T) 2) I = change in momentum = m (delta v)

@andyhughes8315 Жыл бұрын

I'm slightly confused. When a ball is thrown at wall at an angle, shouldn't its rebound angle be the same? Theta initial = -1 * theta final in this case?

@MichelvanBiezen Жыл бұрын

That depends. If there is no friction between the wall and the ball, the incident angle will be the same as the "reflected" angle. But when there is friction, that will not be the case since there will be an impulse in the vertival direction.

@pavithranbalasubramaniam2822 4 ай бұрын

There is energy lost during the impact. So the KE after the impact is less than before. That’s why the angle will change and not be the same.

@djelewis 2 жыл бұрын

My values for Sin(53.1)x20, Cos(53.1)x20, Sin(36.9)x10 & Cos(36.9)x10 are completely different. They are as follows; 6.04, -19.06, -7.17 & 6.97. What am I missing here? Is there another calculation to convert these values to m/s?

@MichelvanBiezen 2 жыл бұрын

Your calculator is in radian mode. You need to reset your calculator into degree mode.

@djelewis 2 жыл бұрын

@@MichelvanBiezen thanks!

@nicobarros6790 9 ай бұрын

Sir, i don't understand why Fy isn't negative, because if the ball is going downwards shouldn't the force in the y-axis be negative?

@MichelvanBiezen 9 ай бұрын

Force is a vector and the magnitude of a vector cannot be negative. Only if we write it in vector format do we need to worry about the sign.

@HelixTheSaint 3 ай бұрын

because the Force_y changes the y velocity postively up, even though at the end it is still negative. Goes from -16 to -6.

@hassanakhtar4264 4 жыл бұрын

We found Fx and Fy but now wouldn’t we use Pythagorean’s theorm to find F by doing the square root of Fx squared and Fy squared?

@MichelvanBiezen 4 жыл бұрын

You can do that or you can simply express the force (which is a vector) as the sum of its components.

@hassanakhtar4264 4 жыл бұрын

Michel van Biezen thank you very much:)

@infinity_x_games2567 3 жыл бұрын

@@MichelvanBiezen Adding them as vectors won't give the same result .Or Will it ?

@rganaiktasl9482 2 жыл бұрын

Sir if the mass hits the wall exactly at 90degrees with a certain speed and bounces off again at 90degrees, so how can we calculate the impulse exerted by the wall on the object? Are we using pythagoras Therom to solve for the impulse?

@MichelvanBiezen 2 жыл бұрын

If the angle is 90 degrees (from the horizontal), technically, the object cannot collide with the wall.

@rganaiktasl9482 2 жыл бұрын

@@MichelvanBiezen so which formula am I going to use sir?

@MichelvanBiezen 2 жыл бұрын

if the ball doesn't collide with the wall then we don't have a collision, so there is no impulse.

@rganaiktasl9482 2 жыл бұрын

@@MichelvanBiezen okay but what about bounces, isn't it the same as collision?

@ranitbanerjee956 2 жыл бұрын

Professor I have a question why after hitting the wall , the ball is not come with the same direction as the action and reaction pair is acting in equal but opposite direction ?

@MichelvanBiezen 2 жыл бұрын

It depends on the amount of friction between the ball and the wall. And the friction only acts in the y-direction, thus energy is lost in the y direction but not in the x direction.

@ranitbanerjee956 2 жыл бұрын

@@MichelvanBiezen is the total energy lost for friction in y direction or some energy lost because after hitting it also moves in y direction.

@MichelvanBiezen 2 жыл бұрын

Energy is a scalar, and therefore is not associated with direction. But the friction force in this case acts in the y-direction only.

@hellothere589 2 жыл бұрын

How do we get Viy tho? like do we do the same Viy = Vi (sin53.1) or? NVM everything ok found it

@MichelvanBiezen 2 жыл бұрын

Great. Keep it going.

@hellothere589 2 жыл бұрын

@@MichelvanBiezen thank you 👍

@luket2195 5 жыл бұрын

Why is the Force in y direction pointed up?

@MichelvanBiezen 5 жыл бұрын

The friction force opposes the motion of the ball.

@ashokdahal1999 3 жыл бұрын

Sir what would happen if a gaseous molecule strike wall inspite of a ball ?? Please

@MichelvanBiezen 3 жыл бұрын

To a molecule, the wall isn't perfectly smooth, but essentially the mechanics are similar.

@yousefmayeli7584 5 жыл бұрын

thanks professor , please keep teaching , we need you

@basudevacharjee9187 Жыл бұрын

Sir, what is the actual change in velocity of the ball

@MichelvanBiezen Жыл бұрын

Vf = SQRT ( Vxf^2 + Vyf^2)

@rahultiwari9003 8 жыл бұрын

sir u did a mistake by taking both the components of Vy as Vysino

@frnchdazzled 8 жыл бұрын

+Rahul Tiwari I tried it myself and i don't see how, could you elaborate ? Because i'm not really good at trig so i might be making a mistake as well.

@WAFBECH3 Жыл бұрын

Arent we supposed to find the resultant force? please help on the question # 11

@MichelvanBiezen Жыл бұрын

We are supposed to find the force required to change the momentum of the ball. (Change in momentum = force x time)

@WAFBECH3 Жыл бұрын

@@MichelvanBiezen I'm cleared 👍. Thanks for clarification

@tsoojbaterdene7793 4 жыл бұрын

An kid is standing 15m away from the brick wall.The kid throws a ball toward the brick wall with 60 degree.Vf=Vo Vf=20m/s final theta= initial theta.In order to catch up the ball how far does the kid have to stand away from the brick wall?I tried to translate from Mongolian,Sir

@MichelvanBiezen 4 жыл бұрын

Do you live in Mongolia?

@tsoojbaterdene7793 4 жыл бұрын

@@MichelvanBiezen Yeah Sir,

@MichelvanBiezen 4 жыл бұрын

Wow that is amazing. I have always been fascinated with Mongolia and I have a huge respect for its people. It is a beautiful but rugged country and the people thrive by working very hard.

@tsoojbaterdene7793 4 жыл бұрын

How about this problem.Do you understand it?

@MichelvanBiezen 4 жыл бұрын

That problem takes a lot of calculations, too complex to try and explain it in a comment, , but it is a very interesting problem. We'll prepare to do a video on it. The answer is 20.3 m

@tsoojbaterdene7793 4 жыл бұрын

theta initial=final theta,Vf=Vo. theta initial is 30 degree,velocity initial is 20m/s.Ball mass is 100g.what will change in impulse be?

@MichelvanBiezen 4 жыл бұрын

Assuming that the "wall" is the horizontal floor and the object is moving from left to right. Then in the x-direction there is no change of momentum. In the y direction impulse = I = change in momentum = I final = I initial = m V final - m V initial = (0.1 kg) (20 m/sec) (sin (30)) - (0.1 kg) (- 20 m/sec) ( sin (30))

@MichelvanBiezen 4 жыл бұрын

Make sure you pay special attention to the signs since momentum is a vector quantity.

@bboymj3628 5 жыл бұрын

do the signs matter there ¿¿¿¿

@MichelvanBiezen 5 жыл бұрын

When working on momentum problems, the direction (and therefore the sign) does matter.

@ItsNoelle. 2 жыл бұрын

what if you don't know the time

@MichelvanBiezen 2 жыл бұрын

If you don't know the time of contact, then you need to know the change in momentum to find the force.

@kauze8063 4 жыл бұрын

Im over here thinking this dude is doing an average value of a function with integrals wth

@hassanhassani2912 7 жыл бұрын

can anyone help me with collisions on linkage systems?

@producer_a_amr7018 4 жыл бұрын

@erwinjedracho640 7 жыл бұрын

sir. i think that you accidentally made a mistake in the value of 20sin(53.1).

@MichelvanBiezen 7 жыл бұрын

Yes, but I caught my mistake.

@erwinjedracho640 7 жыл бұрын

ohh. haha good for you sir..tnx for the help youve been giving me anyway.

@awesomeg7284 9 жыл бұрын

Wait, i thought momentum is always conserved , no matter what. Then , why the concept of impulse is the change in momentum??

@MichelvanBiezen 9 жыл бұрын

awesome Gando When 2 objects collide the sum of their momentum before the collision is equal to the sum of their momentum after the collision When you look at one of the 2 objects in isolation, the change of its momentum is equal to the impulse = F * delta t

@abimaeljr1 9 жыл бұрын

+awesome Gando The conservation of momentum just happens if the net force = 0 , that means Impulse = 0. I hope it helps you.!

@jayashreems18 5 жыл бұрын

Only when there is no external force