Need help - problem Newton laws + my try

[sedaw]

TNX !

http://img377.imageshack.us/img377/8561/00000qj1.jpg

 

[dirk_mec1]

So t =T1. Why is the acceleration 2a in the second equation?

 

[sedaw]

yes T1=t

and m1 distance double m2 distance that`s why the acceleration proportion is 2:1

is that right ?

 

[dirk_mec1]

yes T1=t

and m1 distance double m2 distance that`s why the acceleration proportion is 2:1

is that right ?

No that's not correct where did you get that idea?

 

[sedaw]

can you be more specific , what is not correct and how to solve the problem ?

TNX .

 

[Doc Al]

I don't see anything wrong with your equations. Solve them to find a.

 

[sedaw]

I don't see anything wrong with your equations. Solve them to find a.

t-m_1gsin30=m_1*2a \ *2
+
m_2g-2t=m_2*a


m_1=m_2 = 5kg


2t - 2t - 2*5*0.5g + 5g= 20a+5a

0=25a ====> ?


the answer in the book is a=2.8

how is that ?



pleasez help .

 

[Doc Al]

Oops. It looks like the masses are in equilibrium if they are equal. Are you sure you have the masses correct? (Also, what book are you using?)

 

[sedaw]

Oops. It looks like the masses are in equilibrium if they are equal. Are you sure you have the masses correct? (Also, what book are you using?)

yea i am sure .

the book is classical mechanics by yoram eshel .