If a #2# #kg# object moving at #6# #ms^-1# slows down to a halt after moving #10# #m#, what is the friction coefficient of the surface that the object was moving over?
The object's initial kinetic energy is given by:
This energy will be dissipated doing work against the frictional force acting on the object.
This is the magnitude of the frictional force, which is given by:
To find the frictional force, then:
(coefficients of friction do not have units)
(this is an improbable value for a coefficient of friction - they are typically less than 1, but occasionally as high as 2. Teachers and textbooks do sometimes write questions with these improbable values, though)