Homework Help: Force and Motion(HELP ME)

1. Nov 30, 2011

ljhao1992

1. The problem statement, all variables and given/known data
A ball is rolling on a rough horizontal surface with a deceleration of 2m/s(square). Find the coefficient of kinetic friction between the ball and the surface?

2. Relevant equations

f(k) = u(k)N

3. The attempt at a solution
u(k) = fk/N
i use 2/10

i think my answer is wrong. help me!!!!

2. Nov 30, 2011

Zula110100100

Please supply all known data, i.e. Mass of the ball?

3. Nov 30, 2011

ljhao1992

There are no mass. I am stuck with this qn. I have no idea how to start

4. Nov 30, 2011

trulyfalse

You cannot calculate kinetic friction without mass.

5. Nov 30, 2011

ljhao1992

it dun have mass for this qn. How? Can i able to use w = mg

6. Nov 30, 2011

Zula110100100

Does it tell you the normal force? From where are you getting the 10?

7. Nov 30, 2011

ljhao1992

No. It didn't tell me the normal force. I use g = 10ms(-2 square) g is the gravitational acceleration

8. Nov 30, 2011

Zula110100100

I am at a loss, it seems you need more data, because without the mass of the ball you don't know the force of friction or the normal force, which are both required to find the coefficient of friction, as far as I know