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mc8569
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Homework Statement
Block mass "m" is sliding on frictionless horizontal surface while traveling inside of hoop radius "R". Coefficient of f between block and wall is "u", therefore, speed of block is decreasing. In terms of "R", "v, block's veloc.", "m", and "u", find expressions for:
1. frictional force on the block:
2. block's tangential acceleration (dv/dt).
3. From #2 find time required to reduce speed of block from its original velocity to one-third of its original velocity.
Homework Equations
fk = un
F = ma
ar = v^2/r <-- ar is radial acceleration
The Attempt at a Solution
My process for 1:
fk = un
ar = v^2/R
F = n = ma
n = m(v^2/R)
fk = (umv^2)/R
2:
F = ma
I have no clue on this one.
Would it be from #1, use
v^2 = fR/um
v = sqrt[(fR)/(um)]
And take the derivative of that? And it will be my tangential acceleration?
but the thing is, you have to give the answer in terms of m, R, u, and v only. Can't put in terms of f - friction
3: I assume to be easy with #2? It's just simple kinematics right?
I found a previous inquiry on this problem in the forums but it wasn't very clear, so I wanted to ask it myself.
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