Finding Coefficient of Kinetic Friction

[Ryan Hwang]

Homework Statement

See, I was collecting data for a lab, and now when I look it at, I'm being asked to find the kinetic friction force and the coefficient of friction. What I was given was:
the mass of the block: .261 kg
gravity: 9.81 m/s²
the acceleration: -7.3125 m/s²
And that's it. If it helps we were pushing blocks and used a motion detector to determine the rate of deceleration.

Homework Equations

μ_k*F_N=F_f
F_N=m*g
F_net=m*a

The Attempt at a Solution

Let's say I start with the normal force, which I get 9.81m/s²*.261kg=2.5604N
From there I can't see any more steps I can take. The only forces acting on the object are the friction force, the applied force, which was not measured, gravity, and the normal force. Given the equation and with the task of finding two unknowns, I'm clueless on how to continue.

 

[Nathanael]

So if I understand correctly, you were pushing blocks and then letting go and measuring the deceleration? So the deceleration is measured after you stop pushing on the block?

 

[dean barry]

So, comparison of the force deemed to be retarding the block, and the force of the block on the surface will reveal the friction co-efficient?