Draw a diagram of all the forces acting on block A.

[spriteboost]

Block A, with weight 3w, slides down an inclined plane S of slope angle 36.9 ∘ at a constant speed while plank B, with weight w, rests on top of A. The plank is attached by a cord to the wall (the figure (Figure 1) ).

Part A
Draw a diagram of all the forces acting on block A.
Draw the force vectors with their tails at the center of the block A. The orientation of your vectors will be graded. The exact length of your vectors will not be graded but the relative length of one to the other will be graded.

just stuck on this tried to do it i have vectors
fab friction between ab
fas friction between as
Nb Normal force by plank b
Ns Normal force by plane s
and Wa weight of block a

 

[Simon Bridge]

Welcome to PF;
You can attach pictures to a post - or just describe the diagram.
There is no a,b, or s in your description - did you mean those to be upper-case characters?
For each of the forces you have identified, have you figured out which direction they act?
(Hint: directions can be "up", "down", "along the plane", "perpendicular to the plane", and up or down in relation to the last two.)

 

[spriteboost]

opps sorry didn't upload a picture. Thought I did think I did it this time and I've tried a few different ways and marked me wrong.

 

[Simon Bridge]

Oh there you go - I was hoping you'd draw arrows on it.

curious: 36.5$^\circ$ is an odd angle ... 36$^\circ$ is $\small \pi/5$ radians.
I figure it's random.

 

[Nickie]

I would like to commend you for your effort in attempting to draw a diagram of the forces acting on block A. Based on the given information, we can determine that there are five forces acting on block A: weight (Wa), normal force from the plank (Nb), normal force from the inclined plane (Ns), and two friction forces (Fab and Fas).

To accurately represent these forces in a diagram, it is important to consider the orientation and magnitude of each force. The weight (Wa) will act straight down towards the center of the block A, while the normal force from the plank (Nb) will act perpendicular to the surface of the plank. The normal force from the inclined plane (Ns) will act perpendicular to the surface of the plane.

The two friction forces (Fab and Fas) will act in the opposite direction of the motion of block A, which is down the inclined plane. Therefore, they will be pointing up the inclined plane, with Fab acting between block A and the plank, and Fas acting between block A and the inclined plane. The exact length of each vector does not need to be precise, but it is important to show the relative length of each vector in relation to each other.

Additionally, it is important to note that the weight of the plank B (w) will also act downwards, but since it is attached to the wall by a cord, it will not have a direct impact on the motion of block A. Therefore, it does not need to be included in the diagram of forces acting on block A.

In conclusion, the diagram of forces acting on block A should include five vectors: Wa, Nb, Ns, Fab, and Fas. The orientation and relative length of each vector should accurately represent the forces acting on block A.