- #1
Cooojan
Homework Statement
There is a mass on incline surface that is acted by foces.
μ=0.8
m=2 kg
θ=30°
g=10 m/s^2
##F_N##= normal force
##F_F##= friction force
##Fg_x## = horizontal gravitational component
##Fg_y## = vertical gravitational component
Homework Equations
##F_N=mg~cosθ##
##F_F=μmg~cosθ##
##Fg_x=mg~sinθ##
##Fg_y=mg~cosθ##
The Attempt at a Solution
##∑F_y=F_N-Fg_y=mg~cosθ-mg~cosθ=0##
##∑F_x=Fg_x-F_F=mg~sinθ-μmg~cosθ=mg(sinθ-μ~cosθ)=20(\frac12 -0.8 \frac{√3}{2})=20(-0.193)=-3.86~N##
##a= \frac Fm = -1.93~m/s^2##
This makes absolutely no sense to me.
How can the block have the upward acceleration on the incline... And how can the Friction force be bigger the ##Fg_x##?
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