If the coefficient of kinetic friction between the block and the ceiling’s surface is 0.40, what is the magnitude of the block’s acceleration?

**Answer 1**

The Frictional force Ff is:

Ff=µN

=µ(Fsinθ-mg)

The force parallel to the ceiling Fc is:

Fc=Fcosθ-Ff

this can also be represented as:

Fc=ma

Putting this all together:

a=Fc/m

=(Fcosθ-Ff)/m

=(Fcosθ-µ(Fsinθ-mg))/m

=(86*cos(70)-0.40*

(86*sin(70)-7.0*9.8))/7.0

=3.5 m/s²