Question on working out forces acting on a brick.

[nxtgenlva]

http://imgur.com/MyxXW

Attempt at solution for the last question:
ƩF=f1-f2
Ʃf=25-2.81=22.19N
The force is acting downwards, towards the center of the earth.

Could you lovely people check this over and check if I have it right? Because I have a bad feeling about it.

 

[tal444]

As far as I can see, it looks right to me.

 

[nxtgenlva]

Woohoo! I'm not going to fail A-level physics! Thanks man.

 

[EmittingLight]

What about the friction? Imagine they put the brick on your arm. You would feel a downward force as you have calculated, yes. But if they started pulling the brick, would you feel your arm being pulled too, assuming that there was significant friction?

 

[tal444]

Friction has nothing to do with what the last question is asking.