Finding M1 in a Mass Sliding Problem with an Angle and Friction

[Kpgabriel]

Homework Statement

M1 and M2 are two masses connected as shown.
https://loncapa2.physics.sc.edu/res/msu/physicslib/msuphysicslib/09_Force_and_Motion/graphics/prob75_fricpullplane.gif

The pulley is light and frictionless. Find the mass M1, given that M2 (3.50 kg) is moving downwards and accelerates downwards at 2.99 m/s2, that θ is 20.0°, and that μk is 0.470.

Homework Equations

F = ma

The Attempt at a Solution

So I have broken down the components of the forces especially for M1 because the Mg force has the components sin and cos. I found the force in the y direction of M1 to be Fn=M1gSin(theta). Then I found the x direction to be T(tension)-u(friction)Fn-M1gCos(theta)=M1a. Which would make T= M1(ugSin(theta) + gCos(theta) +a). And for block 2 I have T = M2(g-a). Then I set the T's equal to each other and solve for M1 but it seems to be wrong.

 

[gneill]

Your image isn't showing. No doubt an offsite link to some place that not publicly accessible. Try uploading it instead (use the UPLOAD button at the bottom right of the edit window).

 

[Kpgabriel]

Ok I think I got it

 

[PeroK]

Are you sure you haven't got $\cos$ and $\sin$ mixed up?

 

[Kpgabriel]

Are you sure you haven't got $\cos$ and $\sin$ mixed up?

I did... Thank you so much!