- #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 sence to me.

How can the block have the upward acceleration on the incline... And how can the Friction force be bigger the ##Fg_x##?

#### Attachments

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