Deriving acceleration equation for two-block pulley system

[punyhuman92]

Hey everyone,

First of all, here is the applet so you can see what the problem looks like.

http://session.masteringphysics.com/probhtml/applets/modatt2-14-4a.html

I'm supposed to create an equation for acceleration; using m_1, m_2,Mu_k, and g.


I'm not sure what the first step is;

side question;
is F_t1-F_k=F_net true for this problem? because T2 and and F_g on that side cancel out.

Thank you!

 

[punyhuman92]

Someone please?

 

[punyhuman92]

also the acceleration we're looking for is of the first mass.

 

[NascentOxygen]

For me, that link stalls. You can't include a jpg?

 

[LawrenceC]

Draw a free body diagram for the grey block. You have two forces on it. What are they? Write an equation representing these forces.

Draw a free body diagram for the red block. You have forces on it.
Write an equation representing these forces.

Look at the two equations. You should have two unknowns. Solve for them.

 

[JesseC]

First piece of advice: Draw a diagram of the problem yourself, and label the different forces acting on the two masses taking special care to get the directions of the forces right.

Also considering the applet doesn't work for everyone, might help if you explained the problem in words with a jpg.

 

[punyhuman92]

Thanks guys I got the answer :D
a=(g(m_g-mu_km_r)/(m_r+m_g))