A 5.4 kg wagon is pulled along a horizontal surface. The acceleration of the object is 0.9 m/s^2. What is the coefficient of friction between the surfaces?

Any help is much appreciated! I am not sure how to go about the problem other than I think I must use the Fn (normal force) = Fg (weight) = m(mass) x g (gravitat. field strength).

2 answers

I forgot to mention that the wagon is pulled by a force of 20 N.
Sliding Coefficient of Friction:
http://www.roymech.co.uk/Useful_Tables/Tribology/co_of_frict.htm

Fnet=Fapp-Friction force
ma=20N-(mu)*(N)
since normal force= weight
ma=20N-(mu)*(mg)

solve for mu.