Weight Component: Find Force Components for Box on Inclined Surface

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The discussion focuses on calculating the weight components of a box sliding down an inclined surface at a 30-degree angle. The correct formulas for the weight components are identified as w = mg cos(30) for the perpendicular component and w = mg sin(30) for the parallel component. Participants emphasize the importance of visualizing the problem using a right triangle to understand how the weight force acts vertically, with its components aligned to the incline. There is confusion regarding the application of these formulas, particularly in distinguishing between the horizontal and vertical components relative to the incline. Clarification is sought on the correct use of sine and cosine in the context of the box's movement down the slope.
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Homework Statement


Well I am trying to get help on weight compent. It is a box sliding on an inclined surface with angle 30 degrees.


Homework Equations



w= mg

The Attempt at a Solution



I am trying to find the components for weight force acting on the box. Book says w=mgcos(30) is when its perpendicular to surface, and w= mgsin(30) when its parallel to surface. Can someone explain how to do this?
Thanks
 
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I am trying to find the components for weight force acting on the box. Book says w=mgcos(30) is when its perpendicular to surface, and w= mgsin(30) when its parallel to surface. Can someone explain how to do this?
Thanks
spdowind,welcome to PF! Are you familiar with the method for calculating vector components by drawing a right triangle? Draw a sketch. The weight force acts straight down vertically...that's the hypotenuse of the right triangle. The components are the magnitudes of the legs of that right triangle, one leg parallel to the plane surface, and the other perperpendicular to it. You'll have to do a little geometry and some basic trig to calculate these components. Please show some attempt at this for further assistance.
 
1.jpg

See i am trying to find the horizontal forces for the block sliding down.
I did:
Fx= m* ax
mg*sin(angle)- Tension force - Friction Force= mass * Acceleration.

I just don't understand why I use mg* sin ( angle) instead of mg*cos(angle) when I do the weight x-component minus tension force and friction force.
 
well from my understand again,my graph is a lil off the angle is wrong.
What I do understand is:

The weight is split into 2 components like my graph, but one is horizontal to the sliding surface , one is perpendicular to it, the one horizontal is the X compoent, which means parallel to surface means mgsin(angle)? Am I on the right track? Because I set up my x-y coordinates horizontal to sliding surface and perpendicular to surface.

Thanks
 
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