Question about the Two-Body systems

Ronel

Two blocks of identical material are connected by a light rope on a level surface. An applied force of 55N [right] causes the blocks to accelerate. While in motion, the magnitude of the force friction on the block is 44.1 N. Calculate the acceleration of the blocks.


20 kg|---------------------10kg | -----------------


(sorry about the diagram it looks ugly)

Fnet= Fapp - Ff
Fnet= 55 N - 44.1
Fnet= 10.9N

Fnet=ma
a=Fnet/mt

a=10.9 N/30 kg which is equal to .363

Here's another question: Refer to the information above. The force on friction on the 10-kg block has a magnitude of 14.7 N.

a) calculate the tension in the rope connecting the two blocks

My solution

Ff= μ Fn

μ= Ff/Fn
μ= 44.1/196.2
μ= .2247

I know how to get the Ff2 this is what I did -----> Total Friction(44.1) - 14.7(Ff1 =Friction of 10Kg) = Ff2= 29.2 (20Kg)
My question is can you still answer the a) question without knowing the Friction of 10kg ? (Ff1) I got question a right but just wondering if you can still answer it without know the Friction of 10kg (Ff1).

haruspex

I don't see where you arrive at the tension.
The easiest way is to think about the following ratios:
- frictional force, blk1 v. blk2 v. combined
- accelerational force, blk1 v. blk2 v. combined
- tension in RH rope v. tension in LH rope