Finding force of friction with only applied force and acceleration given?

[Trini_Bwoi]

Homework Statement

What is the value of the force of friction?
Acceleration = 1m/s^2
Applied force = 5.5N

Homework Equations

The Attempt at a Solution

I know what to do if mass or a coefficient of friction were given, but unfortunately they're not!

Any help will be appreciated...

 

[Kurdt]

Are you sure there is no other info given?