physics
posted by Julius .
The alarm at a fire station rings and a 87kg fireman, starting from rest, slides down a pole to the floor below (a distance of 3.9 m). Just before landing, his speed is 1.3 m/s. What is the magnitude of the kinetic frictional force exerted on the fireman as he slides down the pole?

Vf^2=Vi^2+2ad where a= 1/mass (mgfriction)
you know Vf, Vi, mg, and distance d.
solve for frictionforce 
i still cannot solve the problem. can someone please explain it a little bit more?

deg