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myxomatosii
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Homework Statement
Figure P8.36 shows a block of mass m resting on a 20° slope. The block has coefficients of friction µs = 0.83 and µk = 0.47 with the surface. It is connected via a massless string over a massless, frictionless pulley to a hanging block of mass m2 = 2.0 kg.
http://img6.imageshack.us/img6/9688/p836.gif (a) What is the minimum mass m that will stick and not slip?
m_1=1.783kg
(b) If this mimimum mass is nudged ever so slightly, it will start being pulled up the incline. What acceleration will it have?
a_x= ?
Homework Equations
F=ma
T=ma
f_k=μ_k*n
n=m*g*cos(θ)
m_1 = 1.783kg
m_2 = 2.0kg
θ = 20 degrees
T = 19.6N
μ_k = 0.47
μ_s = 0.83
The Attempt at a Solution
I found the mass m_1 using.. (part A)m_1=(T/(μ_s*g*cos(θ)+gsin(θ))
..and I tried to find the a_x using forces.. (Part B begins here)
T - f_k - m*g*sin(θ) = m*a_x
..which gave me the equation...
a_x=(T/m_1)-(μ*g*cos(θ))-(g*sin(θ))
..and I am not sure if I am doing the math wrong but my answers are rejected.
Could anyone perhaps check my force diagram and algebra?
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