# Simplifying SI units

1. Jan 20, 2016

### 1729

1. The problem statement, all variables and given/known data
What physical quantity does $\mathrm{J\cdot N\cdot W^{-1}\cdot kg^{-1}}$ denote?

2. Relevant equations
You can simplify using mechanics equations or ones from electrodynamics. Be creative, I guess.

3. The attempt at a solution
$\mathrm{J\cdot N\cdot W^{-1}\cdot kg^{-1}}$ simplifies to $\mathrm{s\cdot N\cdot kg^{-1}}$. I don't know how to continue from this point.

2. Jan 20, 2016

### Staff: Mentor

Expand the Newton. Think f = ma.

3. Jan 20, 2016

### stockzahn

Do you know the definition of N?

4. Jan 20, 2016

### blue_leaf77

$N$ is unit of force, how can you further write it in terms of fundamental units?

5. Jan 20, 2016

### 1729

Velocity it is. Thanks for the help everyone! I was never taught what the exact definition of the newton was.

6. Jan 20, 2016

### blue_leaf77

Just rewriting units in terms of others does not really require you to know its definition. Just use any formula you know in which force is involved, like work being equal to force times distance (for constant force).