If a #11 kg# object moving at #15 ms^-1# slows down to a halt after moving #225 m,# what is the coefficient of kinetic friction of the surface that the object was moving over?
The coefficient of friction is related to the force acting on the object to accelerate (decelerate) it and the normal force:
First we need to calculate the acceleration (deceleration) of the object:
Now we have an acceleration and a mass and want to find a force... hmm, that sounds a lot like Newton's Second Law to me!
This is the actual magnitude of the frictional force. The coefficient of friction is defined as:
Note that a frictional coefficient is a 'dimensionless' number which does not have units (because it is calculated as a force in