A tile on a roof becomes loose and slides from rest down the roof. The roof is modelled as a plane inclined at 30 degrees to the horizontal. The co-efficent of friction between the tile and the roof is 0.4. The tile is modelled as a particle of mass 'm'kg.
a) Find the acceleration of the particle as it slides down the roof.
Reaction force from the plane = mgcos(angle)
The force of the particle sliding down the plane x = mgsin(angle)
Total force going down the plane is x - Fr=ma
The Attempt at a Solution
R = mgcos(30)
F = uR
Total force down the plane as it is sldiing down is:
mgsin(30) - 0.4mgcos(30) = ma
I can't solve this, as there are TWO unknowns, then theres the fact I can't find m. I've tried looking thorugh text books but no avail.
This is my first post here =) I am attempting to complete as many practice examination questions throughout March and started early instead.
I believe once I answer a), the rest will be easy as well (a needs to be answered for b and c).
Thanks to all!