# Homework Help: Basic kinetic friction and mass quesion?

1. Oct 9, 2012

### nchin

An object of mass M is pulled along a rough floor for some time. An additional mass m is then placed on M and is pulled along the same floor as shown.

(The picture is just a square with mass M and a small square right on top of it with mass m)

What effect does the addition of mass m have on the force of kinetic friction between the floor and mass M?

a. The force of kinetic friction increases.
b. The force of kinetic friction decreases.
c. The force of kinetic friction becomes zero.
d. The force of kinetic friction stays the same.

im leaning more towards a because isnt the more mass an object has, the more kinetic friction it will produce?

also same question except what will happen to the coeffecient of kinetic friction?

a. The coeffecient of kinetic friction increases.
b. The coeffecient of kinetic friction decreases.
c. The coeffecient of kinetic friction becomes negative.
d. The coeffecient of kinetic friction stays the same.

what is the definition of coeffecient of kinetic friction?

2. Oct 9, 2012

3. Oct 9, 2012

### Staff: Mentor

You have some equation/s to support this thinking?

Try wiki, spelling it "coefficient".