Finding Friction with a .26kg Mass at an Angle of 26.1°

AI Thread Summary
The discussion focuses on calculating the static friction force (Ffs) for a 0.26 kg mass on a ramp inclined at 26.1 degrees, with no applied force (Fa = 0). Participants clarify that the system is in static equilibrium, meaning the sum of forces equals zero. The net force equation is established as Fnet = Fll - Ffs, leading to a calculation of Ffa as approximately 1.14 N. It is noted that while static friction implies equilibrium, the problem lacks sufficient information to determine static friction without additional context. The conversation emphasizes the importance of using consistent values for gravitational acceleration in calculations.
Emily266
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Homework Statement


Draw an Fn picture and find Ffs.
mass=.26kg
θ=26.1
Fa= 0


Homework Equations


Fll= mgsinθ
Fnet= sum of all forces parallel to ramp
Fnet= ma


The Attempt at a Solution


I have the picture drawn but I don't know how to find friction.
 
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I assume Ffs is the static frictional force. Therefore, even though you haven't stated otherwise I'll assume that the system is in static equilibrium (ie. the sum of all forces = 0).

Using this information, show us your summation of all the forces.
 
Yes, Ffs was meant to represent static friction. I was unaware that static friction meant that all forces equaled zero.

Fnet=0 so Fll-Ffs

0=1.144-Ffa
-1.144=-Ffa
Ffa=1.14N
 
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If you are given a value for static friction, it does not mean that the sum of forces is zero, I just assumed that considering there is not enough information given (that I can see at least) to solve this question provided the mass has overcome the force of static friction.

Your calculation is ok. Just be aware that most physics questions take acceleration due to gravity to be 9.8 or 9.81 ms-2, however if you've been using 10ms-2 consistently in your class, then it's best not to change it now.
 
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Oh, my teacher did not say that the forces were all equal to zero, just that the applied force was equal to zero.
I don't know if this helps, but this is a lab and we were increasing the angle of a ramp until our mass (a piece of wood with a few weights attached) moved down the ramp. Yeah, our teacher likes to round things.
 
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