Given mass, force, and acceleration solve for the coefficient of friction

[michaelstanle]

Homework Statement

A force of 40.0N accelerates a 5.0-kg block at 6.0M/s^2 along a horizontal surface.
a. What is the frictional force?
b. What is the coefficient of friction?

Homework Equations

u= coefficient of friction
m= mass of object
Ff= friction force
g= gravity

u=Ff/mg

The Attempt at a Solution

I used u=Ff/mg and i got 1.3 for the u. but that is when i used the given acceleration of 6.0 m/s^2, not gravity. is that correct?

 

[tvavanasd]

Did you draw a free body diagram?
You are missing a very important equation.
Did you calculate the friction force?