3 masses and an inclined pulley system

[Hdfjgf]

Homework Statement

The tension between the 6 kg and 4 kg object

a_s=2.1m/s
Fnet = 40N
assume 0.4 kinetic friction coefficent

Homework Equations

T₁- Fnet = ma_s

The Attempt at a Solution

acceleration is negative because the object is decelerating as it goes up the slope
so T₁-40N = 6(-2.1)
T₁ = 27.4 N
So is this right is the tension 27.4 N or do we have to include the mass of the 4kg object in the equation

 

[kuruman]

T₁- F_net = ma_s

Newton's 2nd law says F_net = ma where F_net is the sum of all the forces. Your equation does not make sense. You must first add all the forces to get the net force, then you set what you get equal to mass times acceleration.

Also, it would help us help you if you quoted the problem exactly as it was given to you.

 

[haruspex]

assume 0.4 kinetic friction coefficient

The acceleration you calculated seems to have ignored this.
Once you have the correct acceleration, just consider the forces on the 6kg mass.
As with kuruman, I cannot make sense of your Fnet equation.