Physics 16 Simple Harmonic Motion (7 of 19) Trig Equations w/ Phase Angle

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8 жыл бұрын

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In this video I will show an example of what happens with a phase angle=pi/2 of the trig equation will affect the simple harmonic motion.
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• Physics 16 Simple Har...

Пікірлер: 44

@hazemalaa4771 3 жыл бұрын

great effort, well done! i have a comment if you could explain: isn't the maximum velocity given by Aw? if so, the amplitude should be 50 cm

@rishi0299 8 жыл бұрын

love your videos

@bro8221 2 жыл бұрын

Hey. You didn't use the velocity information so you added an amplitude, but (for other who have not seen it yet..) The v is 5 and the acceleration is 0, when v is 5 as told. therefore you should use a = -A(w^2)cos(wt+phi) , t = 0 because its the equilibrium point, then you find phi, and go back to the velocity equation, find the A and go back to the pistion equation. finding it while you got all the inforamtion you need.

@MichelvanBiezen 2 жыл бұрын

That is correct. In this example, to find the position as a function of time, it was not necessary. To find the velocity as a function of time, or to find the total energy stored, knowing the maximum velocity is necessary.

@johntindell9591 6 жыл бұрын

thank you so much

@WanSyazlina 7 жыл бұрын

So i can use x=A sin(0) then for this question since it started at the equilibrium point towards the right? What if the object has a max velocity that is negative? Does that mean it moves to the left from equilibrium point?

@mido9545 7 жыл бұрын

you can use the function x= A cos (wt -pi/2) as the object has the velocity moving the right, this function is similar to x=A sin (wt) ( you can see the shape of sine function). If the object has the negative max velocity, it tends to shift to the left; therefore, you apply x = A cos (wt +pi/2) (it starts at O and goes toward -A). You actually understand the concept very well

@yehiaelyamani6943 4 жыл бұрын

Or you can use x=-Asin(wt)

@notSavant 7 жыл бұрын

you could derive x(t) to get v(t) and find A

@pablodel61 Ай бұрын

Mr. Van Biezen, I love your videos. I have a question in this case. What is the correct initial condition you mentioned?. I guess the block is pulled first to the given amplitude A=10 cm and then it is released for free vibration, which means that in the initial condition the spring has stored energy, so that block´s velocity is lagged π/2 with respect to displacement x. Is that correct?. Regards from Rosario, Argentina

@alqaisar8774 6 жыл бұрын

Thank you... tomorrow I have my physics finals .. and I'm ready because of your help

@MichelvanBiezen 6 жыл бұрын

Good luck on your finals.

@yossishenberger1285 6 жыл бұрын

Can I find the amplitude by knowing Vmax and using the equation for velocity -Aw sin(wt-π/2) ?

@MichelvanBiezen 6 жыл бұрын

You will still need to know the frequency of oscillation since at maximum velocity v = Aw (1)

@yossishenberger1285 6 жыл бұрын

Thank you. Your videos are very helpful

@CHEESYhairyGASH 3 жыл бұрын

Hi Sir, I have a question, If I start with F=ma, using algebra and calculus I can get to x(t)=Asin(wt), however there is no Psi (phase angle). How does this phase angle "drop out" of the calculus? Have I forgot to add a constant of integration somewhere? Or do we just add the phase angle to the equation ourselves, so that the equation suits the particular situation we happen to be studying?

@MichelvanBiezen 3 жыл бұрын

Very good question. Just like with every integral, there is a constant of integration, which can be determined when you know the initial conditions. So the phase angle depends on where the object is at t = 0.

@CHEESYhairyGASH 3 жыл бұрын

@@MichelvanBiezen I see, I will play around with the numbers tomorrow and change the initial conditions. Thank you for replying so quickly!

@rollmosses1351 4 жыл бұрын

Sir, shouldn’t A be 5cm in this case? Using conservation of energy to calculate A.

@MichelvanBiezen 4 жыл бұрын

It should actually be 50 cm, to be correct. I just grabbed a number without calculating it for a place holder, but I could have calculated it for the correct value. That is a very good observation!

@rollmosses1351 4 жыл бұрын

Got it, thank you sir. You made shm very easy to understand.

@rollmosses1351 4 жыл бұрын

It was a typo, I meant 0.5m.

@hadijaffri9856 2 жыл бұрын

To find x(t) we can also use the function x(t)= Asin(wt) right??

@MichelvanBiezen 2 жыл бұрын

It depends on the initial conditions. It depends on where the object is at when t = 0.

@azad1440 8 жыл бұрын

according to given value max speed is 5m/s by which max amplitude is .5 meter. so your question is wrong. you can also solve by initial energy equal to final energy (K.A^2=M.V^2)

@MichelvanBiezen 8 жыл бұрын

+azad singh You are correct. (and so are the previous viewers who commented). I arbitrarily picked an amplitude, which is incorrect based on the constraint of the maximum velocity. It must indeed be 50 cm (0.5 m) in order to be consistent. Thanks for commenting.

@alexrosellverges8345 4 жыл бұрын

Yeah, i think that's quite important jajajajaj

@t84355 8 жыл бұрын

1) what is the difference if the phase shift is = (3 pi /2) ? 2)when I calculated the amplitude I got 0.5 meters , is that wrong ??

@MichelvanBiezen 8 жыл бұрын

+Thoraia Khaled The maximum amplitude is 10 cm, so the y value can not be larger than that. Also make sure you have your calculator in radian mode.

@mannykay1 4 жыл бұрын

Hey! so are you assuming that this is a function with a period of 2PI radians because you say that -pi/2 shifts the function to right by a quarter of a period. The makes sense to me...However then I assume that the period is not 2pi radians because your value for omega is 10. Shouldn't omega be equal to 1 in order to assume a period of 2pi radians? I DO NOT understand...maybe there is flaw in my fundamentals of graphing sinusoidal functions but I cant understand this...

@MichelvanBiezen 4 жыл бұрын

We have a number of videos in this playlist (under precalculus) that describes this very systematically: TRIGONOMETRY BASICS - PRECALCULUS 6

@lacceybird 6 жыл бұрын

should my calculator be in radians or degrees

@MichelvanBiezen 6 жыл бұрын

For this it should be in radians

@irinabursill6979 3 ай бұрын

Thank you

@MichelvanBiezen 3 ай бұрын

Glad you find this helpful.

@arrushahuja126 4 ай бұрын

shouldn't the max amplitude be 0.5 m as we already have vmax and vmax = w*A. A here should be 0.5 as we know v max = 5 and w = 10

@MichelvanBiezen 4 ай бұрын

Yes indeed, you caught the inconsistency in the problem. When I put numbers on the board (at random) I didn't check that the amplitude was consistent with the maximum velocity. Good catch.