MHB Mechanics- connected particles

[Shah 72]

A bucket of mass 3kg rests on scaffolding at the top of a building. The scaffolding is 22.5m above the ground. The bucket is attached to a rope that passes over a smooth pulley. At the other end of the rope there is another bucket of mass 3kg, which initially rests on the ground. The bucket at the top of the building is filled with 6kg of bricks and is gently released. As this bucket descends the other bucket rises.
Find how long it will take the descending bucket to reach the ground.
I have no clue how to solve this.
Initially the acceleration is zero as both the buckets are at rest. R= 90N for the top bucket and T= 30N for the bottom bucket.

 

[topsquark]

What have you tried? Did you start by sketching out a Free Body Diagram?

-Dan

 

[Shah 72]

What have you tried? Did you start by sketching out a Free Body

 

[Shah 72]

What have you tried? Did you start by sketching out a Free Body Diagram?

-Dan

I think I realized where I have done the mistake. I need to calculate the F= m×a of the 9kg bucket going down taking its acceleration as negative and the bucket of 3 kg coming up acceleration as positive. I get t= 3s
Is this the right way? My freeborn diagram is wrong for the bucket that's on the top

 

[skeeter]

 

[Shah 72]

View attachment 11159

Thank you!