If a #3 kg# object moving at #20 m/s# slows to a halt after moving #500 m#, what is the coefficient of kinetic friction of the surface that the object was moving over?
The only horizontal force acting on the object is kinetic friction:
We know that the object is travelling at
giving an acceleration of:
Finally we can use Newton's second law to equate the resultant of the forces acting on the object to mass and acceleration:
BUT: horizontally, the only force acting on the object is friction (IN OPPOSITE DIRECTION TO THE MOTION ) so that we can write: