SHM Booster Class 1 Physics Galaxy

Topics Covered: a) SHM as UCM b) Same Ampltitude Same Mean Position Double SHM c) Same Mean Different Amplitude SHM (Crossing + Overtaking +Meeting <---- 3 cases)

Imp: Maximum distance between particles in double SHM having constant phase difference occurs when they are in a st.line parallel to diameter along which projection is being taken.

SHM Booster Class 2 Physics Galaxy

@Yashas Have a look at this question ^ I'm confused. When an identical body is attached to the bob at distance $l\alpha/2$ won't the $A$ change? If the $A$ changes then even though the $\omega$ remains same the angle between that middle position and mean won't be $\pi/4$. Shouldn't the time taken be $\frac{\pi/4}{\omega}+\frac{\sin^{-1}(\frac{l\alpha/2}{A'})}{\omega}$

Where $A'$ is the new amplitude

SHM Booster Class 3 Physics Galaxy

@Koolman Etoos...

Yes

@Koolman You want to solve an SHM question?

I've got a good one

Okay 1 min

Find angular frequency!

The block m is pulled down a bit and left

What is the angular frequency of oscillation of the system?

(No slipping anywhere)

Cylinder

$M$

Mass of block is $m$

And cylinder is $M$

@TheDeadLegend I know the solution. This is a quiz. And I want the solution by the force method.

@Koolman There will be around 5 or 6 equations. You need to check your calculations properly

It must come

You can write your equations here

Energy method doesn't provide one the insight that force method provides.

It is more of a shortcut

@TheDeadLegend Secondly that equation is wrong. If block goes down by $x$ spring doesn't extend by $2x$.

@Koolman Where are the eqm conditions?

@Koolman This is wrong

There is an initial extension in the spring

You didn't take that into account

Okay, then?

You don't need to...just take it as $f_o$

Yes, even tension will change

@Koolman How did you get the $2$ there?

Oh, that's the torque equation

Fine

Your mistake is while writing $x$. Relate the distance x by which block goes down with the distance by which spring is extended

You messed up by writing $x=x_o+x'$

Take initial extension as $h$ and extra distance by which block moves down as $x$

How is $a$ coming to be proportional to $x$ ?

@Koolman Will I write my equations?

@samjoe @Koolman The answer is $$\sqrt{\omega=\frac{16k}{9m+6M}}$$.

Force Method:

$\frac{3}{2}mg=2kh_o$

$k(h_o+\frac{4}{3} x) + f - (ma+mg) = M (\frac{2}{3} a)$

$k(h_o+\frac{4}{3} x) R -fR - (ma+mg)\frac{R}{2} = (\frac{1}{2} MR^2)(\frac{2}{3}a)$

@user123733 Take reflection of (-1,1) on x axis. Find shortest distance of that point from parabola! Done!

@user123733 Oh sorry, I didn't notice you already got an answer.

@user123733 Why do you want to change the coordinate system? That would unnecessarily complicate it.

@user123733 You can get (2,2) by observation

Or else, if you really want you can put x-y=Y and x+y-4=X and shift the origin. Find shortest distance using calculus.

@user123733 You can find the axis of the parabola. Can't you?

You will see that (2,2) and (-1,-1) both lie on the axis

@Programmer Indeed

Did you learn any chapter ?

From there?

@samjoe This is basically because (D) is more stable due to maximum hyperconjugation. 6 alpha hydrogens are created due to the double bond shift.

You'll can easily predict this if you have learnt GOC well

(Remember that you have only 1 eq of HBr)

@Sid No. In case of Br2 the mechanism is quite different. That takes place through a non classical carbocation mechanism.

This is the mechanism that occurs for Br2 addition. ^

@samjoe You need to follow proper study materials/books.

School books don't teach them in detail.

@Sid "I know that works on the basis of carbocations too." It doesn't. Source?

This is the basic mechanism for HBr.

@Sid That is for HBr.

This is called classical carbocation mechanism.

For Br2 non classical mechanism is followed.

Check Morrison Boyd or LG Wade for details.

@Sid Offline. It was okay. Yours?

Ah, well. 180 isn't bad! :)

You rank should be around 12k I expect?

Well, even I did that mistake. Ticked Cr(3+) in excitement :P Ended up getting 225. I was expecting 250+. But meh :/. In maths I got only about 60.

Oh, chemistry was quite easy. It was from NCERT mostly.

Maths went bad for me.

Physics was okay. Got 85.

About 2 months I suppose.

chat.stackexchange.com/rooms/info/54160/jee-preparation

Check the info on that link ^

It states the date of first message.

Yes. But not preparing...

as such

After JEE

2 days later

yea

English...