How to solve this Physics Problem

[Shweta_S]

Hi,
In the fig attached Two mass M passes through Pulley
The Mass M moves with velocity u
What is the velocity of Mass K

Please provide explnation
Thanks[/img]

 

[echo47]

I don't see any attached figure.

 

[Shweta_S]

sorry missed that
here it is

thanks

 

[zorro]

It is u/cos(x).
Draw the situation after a small time dt, and with some geometry you get the result.
Regards

Z

 

[Shweta_S]

Thanks

 

[Kral]

sfunds,
I'm assuming that "X" is the angle between the rope and vertical.
Velocity of a point on the rope(Vr) = velocity of M (Vm).
Then
Vk = Vm Cos(X)
Regards,
Kral

 

[Shweta_S]

is it u/cos(x) or ucos(x) i am now confused can zorro post how he arrived at it. i thought i can arrive at it but couldnt pl post how you arrived at it

 

[nijirazdan]

this is an easy problem.just resolve the tension into corresponding components n then using f=mg get the result

 

[THz]

this is an easy problem.just resolve the tension into corresponding components n then using f=mg get the result

How can the known force be used for solving velocity?

 

[Shweta_S]

Hi,

The answer zorro gave is right one my professor said but he didnt explain.
Zorro can you please explain

Thanks

 

[zorro]

Here it is:

The movement of the three masses is vertical.
The length of the cord does not change.
So, when the mass M moves vertically an amount dym (downwards), in the same time the mass K moves vertically (upwards) an amount dyk such that the portion of the cord between the pulley and the new position of K is dym shorter.
Draw the positions at two times dt apart, such that the angle between the 1st and the 2dn position of the cord very small.
Draw a normal to the cord at the 1st position passing by K at the 2nd position. It is also normal to the cord at the 2dn one as dt->0.
Observe that dym=dyk*cos(X) [regardless of signs].
The speed of M is u=dym/dt; the speed of K is dyk/dt = u/cos(X).
Regards

Z

 

[Shweta_S]

Hi,
Thanks zorro