Question

Please help! I don't know how to solve this problem:
A 1.8 kg block slides across a rough surface such that it slows down with an acceleration of 1.15 m/s^2. What is the coefficient of kinetic friction between the block and the surface?

Answer 1

Coefficient of kinetic friction can be found using this formula
\[\mu=\frac{ F _{fr} }{ F _{n} }\]
- u is the coefficient of kinetic friction
- Ffr is the force due to friction
- Fn is the normal force acting on the box

Answer 2

I dont have mass so how do I find the coefficient without it?

Answer 3

You are given the mass in the question- 1.8 kg

Answer 4

Oops sorry. I have tried with that equation but I can't seem to figure it out

Answer 5

The frictional force(Ffr) can be found using the formula
\[F _{fr}=ma\]
- m is the mass
- a is the acceleration

Answer 6

and the Normal force(Fn) is equal to the force due to gravity since there is no vertical motion. Therefore,
\[F _{n}=mg\]
- g is the acceleration due to gravity(constant)

Answer 7

I get it, thank you!