Sphere on an incline plane against a wall

AI Thread Summary
The discussion revolves around analyzing the forces acting on a sphere resting on an inclined plane against a wall. Key forces include gravitational force, normal forces from the incline and the wall, and friction, with the assumption that surfaces are smooth unless stated otherwise. Participants emphasize the need to correctly identify and name all relevant forces before formulating equations, as the initial equations presented are deemed incorrect due to missing terms and unclear definitions of normal forces. There is a focus on the importance of resolving forces in two directions to establish statics equations accurately. The conversation highlights the necessity of clarity in problem statements and the correct application of physics principles to solve the problem effectively.
ethan340
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Homework Statement


Find all of the forces acting on the sphere. The problem must be solved in variables. A sphere, mass m, is resting on an incline plane at θ relative to the horizontal. The sphere is also resting against a perpendicular wall relative to the horizontal. Gravity = g.

Homework Equations


f perp. to incline plane= mg(cos θ)
f parallel = mg(sin θ)
fnormal = g

The Attempt at a Solution


Setting up those equations was as far as i got; i still need the force of the sphere against the wall perpendicular to the ground i think
 
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The question ought to state that the surfaces are smooth, otherwise it's indeterminate.
Anyway, your equations are wrong: the first two because they omit any force from the wall; the third because it equates a force to an acceleration, and besides, fnormal is normal to what?
Before writing equations, list and name all the forces that are relevant, stating whatever is known about the directions in which they act and their lines of action. Then choose two directions in which to resolve and write the statics equations.
 
haruspex said:
The question ought to state that the surfaces are smooth, otherwise it's indeterminate.
Anyway, your equations are wrong: the first two because they omit any force from the wall; the third because it equates a force to an acceleration, and besides, fnormal is normal to what?
Before writing equations, list and name all the forces that are relevant, stating whatever is known about the directions in which they act and their lines of action. Then choose two directions in which to resolve and write the statics equations.

haruspex, i appreciate that you've taken the time to read my post and convey what you believe is helpful to me, but unfortunately, your post isn't all that helpful to me. you fail to understand the difference between incorrectness and incompleteness, and the fact that you don't know what i mean by normal force worries me that you aren't qualified to answer this question. by the way, the surface is smooth unless specified otherwise.

in any case, i would like advice on how to solve the problem correctly and understand the methodology behind it.
 
ethan340 said:
you fail to understand the difference between incorrectness and incompleteness
If an equation is missing a term it is incorrect.
, and the fact that you don't know what i mean by normal force worries me that you aren't qualified to answer this question.
I know what a normal force is, but it doesn't mean much unless you specify the plane it's normal to. In this case, you already have "f perp. to incline plane", so I guess it's not that. The only other surface of contact is the wall, but normal to the wall would be horizontal.
You have it equal to g (but you probably mean mg), so it sounds like a vertical force.
 
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