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## Homework Statement

A box of textbooks at unknown mass rests on a loading ramp that makes an angle α = 16o with the horizontal. The coefficient of static friction is 0.30, and kinetic friction is 0.25. Then the box is released. (a) Will it start sliding down the ramp? (a) Find the normal force on the box (b) If it slides down then find the acceleration of the box

**2. Relevant**

∑F=ma

∑

ƒ=µn

## The Attempt at a Solution

Forces in x-direction:

w-ƒstatic=0

w=ƒstatic

mgsin(16)=µn

y: n-w=0

n=w

n=mgcos(16)

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mgsin(16)=µmgcos(16)

sin(16)=µcos(16)

sin(16)/cos(16)=µ

But already know µ so this doesn't help me...

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