A tree trunk, of mass 250kg, is pulled up a slope by a chain attached to a tractor.

The chain is at an angle of 10 degrees to the slope. The slope itself is at 8 degrees to the horizontal.

The tree trunk initially accelerates at 0.2 ms^{-2}. A friction force, of magnitude 2000N, acts on the tree trunk.

(a) Modelling the tree trunk as a particle, find the initial tension in the chain.

(b) Explain why the tension in the chain will probably decrease.

I have answered part (a) correctly by using Newton's 2nd law parallel to the slope (Tension = 2428 N) but I am struggling with part (b).

The answer at the back of the book states "".The resistance force will increase and it will stop accelerating

The questions I have are:

1. Why will the resistance force increase?(Maybe due to air resistance?)

2. Why, if it stops accelerating, will the tension in the chain decrease?

Any help would be gratefully appreciated!